Karsten Olsen - Academia.edu (original) (raw)

Papers by Karsten Olsen

Research paper thumbnail of Umami synergy as the scientific principle behind taste-pairing champagne and oysters

Scientific Reports, Nov 18, 2020

Research paper thumbnail of Protein changes in shell and epidermis of shrimp (Pandalus borealis) after maturation on ice or in salt

Research paper thumbnail of Effect of industrial process conditions of fava bean (Vicia faba L.) concentrates on physico-chemical and functional properties

Innovative Food Science & Emerging Technologies

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Formation of α-Dicarbonyls from Dairy Related Carbohydrates with and without Nα-Acetyl-l-Lysine during Incubation at 40 and 50 °C

Journal of Agricultural and Food Chemistry, 2019

-Dicarbonyls are reactive intermediates formed during Maillard reactions and carbohydrate degrad... more -Dicarbonyls are reactive intermediates formed during Maillard reactions and carbohydrate degradation. The formation of seven -dicarbonyls was characterized in solutions containing dairy related carbohydrates (galactose, glucose, lactose, and galacto-oligosaccharides (GOS)) during incubations at 40 ºC and 50 ºC with and without Nα-acetyl-L-lysine at pH 6.8 for up to 2 months. The concentrations of -dicarbonyls in samples of monosaccharides with Nα-acetyl-L-lysine were found to be: 3-deoxyglucosone (3-DG) > 3-deoxygalactosone (3-DGal) > glyoxal > glucosone, galactosone > methylglyoxal > diacetyl. The presence of Nα-acetyl-Llysine resulted in up to 100-fold higher concentrations of C6 -dicarbonyls, but lesser formation of glyoxal in the monosaccharide-containing models compared to what was observed in the absence of Nα-acetyl-L-lysine. Galactose incubated with Nα-acetyl-L-lysine generated the highest concentrations of 3-DGal (up to 130 µM), glyoxal (up to 100 µM) and methylglyoxal (up to 9 µM) compared to the other carbohydrates during incubation. Surprisingly, 3-DG (1500 µM) and 3-DGal (80 µM) were formed at levels of two orders of magnitude higher in solutions of GOS in the absence of Nα-acetyl-L-lysine as compared to the other carbohydrates at 40 ºC while GOS generated the lowest levels of glyoxal. GOS is widely used as an ingredient in various types of foods products, and it is therefore of importance to consider the risk of generating high levels of the reactive C6 -dicarbonyl, 3-DG in these types of products. This study contributes to the understanding of major -dicarbonyl formation as affected by the presence of primary amines in GOS, lactose, and galactose containing solutions under moderate heating in liquid foods.

Research paper thumbnail of Gastrophysical and chemical characterization of structural changes in cooked squid mantle

Journal of Food Science, 2021

Squid (Loligo forbesii and Loligo vulgaris) mantles were cooked by sous vide cooking using differ... more Squid (Loligo forbesii and Loligo vulgaris) mantles were cooked by sous vide cooking using different temperatures (46°C, 55°C, 77°C) and times (30 s, 2 min, 15 min, 1 h, 5 h, 24 h), including samples of raw tissue. Macroscopic textural properties were characterized by texture analysis (TA) conducted with Meullenet‐Owens razor shear blade and compared to analysis results from differential scanning calorimetry. The collagen content of raw tissues of squid was quantified as amount of total hydroxyproline using ultra‐high‐performance liquid chromatography. Structural changes were monitored by Raman spectroscopy and small‐angle X‐ray scattering and visualized by second harmonic generation microscopy. Collagen in the squid tissue was found to be highest in arms (4.3% of total protein), then fins (3.0%), and lowest in the mantle (1.5%), the content of the mantle being very low compared to that of other species of squid. Collagen was found to be the major protein responsible for cooking los...

Research paper thumbnail of The physical stability of plant-based drinks and the analysis methods thereof

Food Hydrocolloids, 2021

Plant-based drinks have increasingly become a regular product in the market. The range of raw mat... more Plant-based drinks have increasingly become a regular product in the market. The range of raw materials available creates an abundance of products with various properties. For product optimization purposes, it is imperative to fully characterize the product, especially in terms of its physical stability. This review aims to summarize the techniques currently available to characterize and understand the underlying factors describing the physical stability of plant-based drinks. The methods discussed range from general methods that have been widely used to specific fingerprinting spectroscopic techniques such as UV-VIS, FTIR, NIR, Raman, Fluorescence Spectroscopy, and NMR. The benefit and trade-off of each method is discussed in relation to its application for plant-based drink products. In addition, the classic colloid theory (the electric double layer) is mentioned to explain the separation phenomena which follow the discussion on available mechanisms to improve the system (electrostatic and steric stabilization mechanism).

Research paper thumbnail of Effects of high pressure and ohmic heating on shell loosening, thermal and structural properties of shrimp (Pandalus borealis)

Innovative Food Science & Emerging Technologies, 2019

This study aimed at understanding the effects of high pressure (HP) and ohmic heating (OH) on the... more This study aimed at understanding the effects of high pressure (HP) and ohmic heating (OH) on the peelability, the underlying mechanisms of HP-and OH-induced shell tightening, the thermal and structural properties of shrimp parts. HP improved the peelability of shrimp at low pressure level (<350 MPa) and short holding time (≤3 min) and the optimum condition for peeling was at 100 MPa for 3 min at 5°C. However, a higher pressure level (>350 MPa) led to a decrease in the peelability. High pressure at 600 MPa stabilized cuticular and epidermal collagen and formed new collagen-like structures by new linkages, which strengthened the muscle-shell connection and reduced the peelability. Shrimp meat induced from HP at 100 MPa and 600 MPa had minorly denatured myofibrillar proteins. OH as a blanching method did not significantly improve the peelability of shrimp at most of the studied conditions. Some extreme conditions (e.g. at 50°C) caused a markedly low peelability due to occurrence of collagen gelatinization. The gel formation from collagen-gelatin transformation under heating added strength to adherence of shell to epidermis and muscle, as a consequence, a difficult peeling was experienced. OH also denatured proteins in shrimp meat and caused loss of astaxanthin. Industrial relevance: The industrial processing of ready-to-eat shrimp involves the on-ice or in-brine maturation process which loosens the shrimp's shell from its meat, and therefore enable the mechanical peeling. However, the traditional maturation is time consuming (up to 4-5 days), inevitably leads to reduced quality of shrimp meat. This study shows the possibility of the application of HP at mild pressure levels to promote the shell loosening at short HP processing time (≤3 min). However, at more severe HP conditions could lead to the shell tightening which was caused by HP-induced stabilization of collagen in shell and epidermis. The study also shows that ohmic heating (<5 min) might not be a significant blanching method to support the maturation since OH had minor positive effect on shell loosening at 3 some OH conditions (e.g. 2 or 10% NaCl, 92V, and 30 or 35°C), but had a counter effect at most OH conditions especially at high temperature.

Research paper thumbnail of Squids of the North: Gastronomy and gastrophysics of Danish squid

International Journal of Gastronomy and Food Science, 2018

Several species of cephalopods, particularly squid, are present in Danish waters, but neither are... more Several species of cephalopods, particularly squid, are present in Danish waters, but neither are they fished commercially nor are they part of the Danes' traditional diet. However, if Danes can eat octopus, squid, and cuttlefish when visiting Southern Europe why do they hesitate to eat Danish cephalopods at home? Cephalopods are a nutritious, healthy, and sustainable source of seafood. Moreover, the populations of all species of cephalopods are globally on the rise in stark contrast to the dwindling traditional fisheries. Eating more of them is a way to a more insightful and sustainable use of the marine food resources. The challenge is how to prepare them into delicious 2 food and how to make the Danish population, the fishermen, and the retailers aware of their great potential and value as sustainable and delicious food. We have combined scientific gastrophysical investigations of various squid preparations with gastronomical design, innovation, development of recipes, and inventive product design to furnish a solid basis for spreading knowledge, appreciation of flavour, and a desire to consume Danish squid in Denmark.

Research paper thumbnail of Facilitating shrimp ( Pandalus borealis ) peeling by power ultrasound and proteolytic enzyme

Innovative Food Science & Emerging Technologies, 2018

The potential of power ultrasound (24-kHz frequency) as an individual treatment and in combinatio... more The potential of power ultrasound (24-kHz frequency) as an individual treatment and in combination with proteolytic enzyme to promote the shell-loosening of cold-water shrimp (Pandalus borealis) was investigated. Textural properties of shrimp were highly dependent on temperature control during the ultrasonic process (27.6-μm amplitude, 120 min duration and 0.9-s pulse), while the peelability of shrimp monitored as peeling work, meat yield and proportion of completely peeled shrimp were less dependent on the temperature. Increasing amplitude (0-46 µm) and time (0-45 min) of ultrasound prior to enzymatic maturation (0.5% Endocut-03L, 6 h, and 3 °C) increased the peelability of shrimp. The parallel combination of ultrasound and enzyme (18.4-μm amplitude, 0.9-s pulse, 0.5% Endocut-3L, 3-h and 4-h duration, and T ≤ 5 °C) considerably improved the shrimp peelability without detrimental effect on the texture and color of shrimp. Ultrasound was found to inactivate proteolytic enzyme in solution and to modify the structural properties of shrimp shells. From scanning electron micrographs (SEM), we proposed a mechanism for the ultrasound-enzyme-induced shell-loosening based on ultrasonic shell surface erosion and enzyme diffusion. Cavitation bubbles generated from sound waves pitted the surface of shrimp shell, generating pathways for enzyme diffusion into the muscle-shell attachment.

Research paper thumbnail of Morphology and Structure of Solid Lipid Nanoparticles Loaded with High Concentrations of β-Carotene

Journal of Agricultural and Food Chemistry, 2019

Research paper thumbnail of Proteomic and microscopic approaches in understanding mechanisms of shell-loosening of shrimp (Pandalus borealis) induced by high pressure and protease

Food Chemistry, 2019

Microstructure, protein profile, relationship between shrimp shell-loosening and protein, and mec... more Microstructure, protein profile, relationship between shrimp shell-loosening and protein, and mechanisms of shell-loosening after high pressure (HP) and enzyme treatment were investigated. The shell-loosening gap induced by an endoprotease with broad specificity (Endocut-03L) was much higher (53 μm) than that induced by HP at 100 MPa (HP100, 12 μm), followed by an endoprotease with high specificity (8 μm), and HP at 600 MPa (5 μm). The extent of protein changes in epidermis and shell corresponded with the shell-loosening gap. Thus, the gap could be predicted by the fold change of protein spots by a PLS model. Shell-loosening due to HP100 and Endocut-03L was mainly caused by physical and enzymatic degradation of high molecular-weight proteins in shell and epidermis and subsequent loss of degradation products, disrupting the structure of muscle-shell connection. However, HP100 was less effective than Endocut-03L due to its stabilizing effect on the shell collagen, lowering its shell-loosening effect.

Research paper thumbnail of Inhibition of Maillard Reactions by Replacing Galactose with Galacto-Oligosaccharides in Casein Model Systems

Journal of Agricultural and Food Chemistry, 2018

Lactose reduced dairy products are more prone to Maillard reactions due to the presence of reacti... more Lactose reduced dairy products are more prone to Maillard reactions due to the presence of reactive monosaccharides. Conventional β-galactosidases, which are used for lactose hydrolysis in lactose reduced dairy products, will lead to conversion of lactose into glucose and galactose, where especially galactose is very reactive during Maillard reactions. Some βgalactosidases have transgalactosylating activity, and will thus convert lactose into galactooligosaccharides (GOS) and hereby limit the release of galactose. The aim of this study was to investigate the extent of participation of GOS in Maillard reactions in comparison to lactose, a 50:50 mixture of glucose and galactose, and galactose exclusively in sodium caseinate based milk-like model systems heated at 130 o C and 75 o C at pH 6.8. The GOS system exhibited reduced loss of free amino groups, accumulated less furosine and less of the following advanced glycation end products (AGEs): N -carboxyethyl lysine (CEL), methylglyoxalderived hydroimidazolone isomers (MG-H), glyoxal-derived lysine dimer (GOLD), and methylglyoxal-derived lysine dimer (MOLD), and also developed less browning compared to monosaccharide models. However, the GOS-caseinate system accumulated more 3deoxyglucosone and 3-deoxygalactosone, which resulted in higher concentrations of 5-(hydroxymethyl)furfural and pyrraline. The results indicated that GOS overall participate less readily in Maillard reactions than the monosaccharides investigated, but were more prone to degradation to C6 -dicarbonyls species. Finally, relationship analysis indicated that C6 dicarbonyls seemed to primarily increase concentrations of 5-(hydroxymethyl)furfural instead of AGEs. Our results suggest that conversion of lactose into GOS instead of monosaccharides in milk by transgalactosylating β-galactosidases could be a useful strategy for production of lactose-free milk for people with lactose-intolerance.

Research paper thumbnail of A Comprehensive Approach to Assess Feathermeal as an Alternative Protein Source in Aquafeed

Journal of Agricultural and Food Chemistry, 2017

The effect of partially replacing fishmeal in aquafeed with feathermeal (FTH) at three levels (0%... more The effect of partially replacing fishmeal in aquafeed with feathermeal (FTH) at three levels (0%: FTH0, 8%: FTH8, 24%: FTH24) and two extrusion temperatures (100 and 130 °C) were evaluated in rainbow trout (Oncorhynchus mykiss) with respect to growth 4 performance, metabolism response, and oxidative status of the feed proteins. Multivariate 5 data analyses revealed that FTH24 correlated positively with high levels of: oxidation products, amino acids (AA) racemization, glucogenic AAs level in liver, feed intake (FI), specific growth rate (SGR), and feed conversion ratio (FCR); and low AAs digestibility. Both FI and SGR were significantly increased when 8 and 24% feathermeal was included in the feed extruded at 100 °C, while there was a negative effect on FCR in fish fed FTH24. In conclusion, higher oxidation levels in FTH24 may give rise to metabolic alterations while lower levels of FTH may be considered as fishmeal substitute in aquafeed for rainbow trout.

Research paper thumbnail of Casein micelle dissociation in skim milk during high-pressure treatment: Effects of pressure, pH, and temperature

Journal of Dairy Science, 2010

The effect of pH (from 5.5 to 7.5) and temperature (from 5 to 40°C) on the turbidity of reconstit... more The effect of pH (from 5.5 to 7.5) and temperature (from 5 to 40°C) on the turbidity of reconstituted skim milk powder was investigated at ambient pressure and in situ under pressure (up to 500 MPa) by measurement of light scattering. High-pressure treatment reduced the turbidity of milk for all combinations of pH and temperature due to micelle dissociation. The turbidity profiles had a characteristic sigmoidal shape in which almost no effect on turbidity was observed at low pressures (100 MPa), followed by a stronger pressure dependency over a pressure range of 150 MPa during which turbidity decreased extremely. From the turbidity profiles, the threshold pressure for disruption of micelle integrity was determined and ranged from 150 MPa at low pH to 350-400 MPa at high pH. The threshold pressure diagram clearly showed a relationship between the barostability of casein micelles and pH, whereas almost no effect of temperature was shown. This remarkable pH effect was a consequence of pressure-induced changes in the electrostatic interactions between colloidal calcium phosphate and the caseins responsible for maintaining micellar structure and was explained by a shift in the calcium phosphate balance in the micelle-serum system. Accordingly, a mechanism for high pressure-induced disruption of micelle integrity is suggested in which the state of calcium plays a crucial role in the micelle dissociation process.

Research paper thumbnail of Riboflavin-sensitized photooxidation of isohumulones and derivatives

Photochemical & Photobiological Sciences, 2004

Isohumulones, the bitter principles in beer, are decomposed by light-induced reactions, thereby a... more Isohumulones, the bitter principles in beer, are decomposed by light-induced reactions, thereby adversely affecting beer quality. Upon absorption of visible light, riboflavin is excited and interacts with isohumulones, as well as with oxidized and reduced derivatives thereof. Reaction kinetics were investigated by laser flash photolysis at 355 nm and at 440 nm, and analysis of kinetic data afforded detailed insights into the reaction mechanism.

Research paper thumbnail of Stopped-flow kinetic studies of the reaction of barley α-amylase/subtilisin inhibitor and the high pI barley α-amylase

FEBS Letters, 1995

The interaction of a-amylase/subtilisin inhibitor (BASI) from barley seeds and the high pI barley... more The interaction of a-amylase/subtilisin inhibitor (BASI) from barley seeds and the high pI barley a-amylase (AMY2) de novo synthesized during seed germination, has been studied at pH 8.0, 25°C, using stopped-flow fluorescence spectroscopy, equilibrium fluorescence titration and kinetic analysis of the displacement of BASI from the BASI-AMY2 complex by the substrate blue starch. The results are in accordance with a two-step reaction model: xl 42 BASI + AMY2 ~ BASI-AMY2 ~ BASl-AMY2* /;-2 The resulting values of the kinetic parameters were: k21K l = (1.0 + 0.2) × 106 M-1 "s-i,/(i = 0.4 + 0.21 mM, k 2-320 + 150 s-1, k_ 2 = (7.2 + 0.6) × 10-Ss-1, and the overall dissociation constant Kd = (0.7 + 0.1) × 10-1° M. BASI thus is best characterized as a fast reacting, tight-binding inhibitor of AMY2.

Research paper thumbnail of Two Statistical Tools for Assessing Functionality and Protein Characteristics of Different Fava Bean (Vicia faba L.) Ingredients

Foods, 2021

Fava bean (Vicia faba L.) is a promising source of proteins that can be potentially used as nutri... more Fava bean (Vicia faba L.) is a promising source of proteins that can be potentially used as nutritional and/or functional agents for industrial food applications. Fava ingredients are industrially produced, modified, and utilized for food applications. Their processing conditions influence physico-chemical protein properties that further impact ingredient functionality. To design a functionally suitable ingredient, an understanding of the interrelationships between different properties is essential. Hence, this work aimed to assess two statistical analytical tools, Pearson’s correlation and Principal Component Analysis (PCA), for investigating the role of the process conditions of fava ingredients on their functional and protein properties. Fava concentrates were processed by pH (2, 4, 6.4 and 11), temperature (55, 75 and 95 ∘C) and treatment duration (30 and 360 min) into different modified ingredients. These were utilized under two application conditions (pH 4 and 7), and their fo...

Research paper thumbnail of Effect of ice maturation, freezing and heat treatment on the peelability and quality of cold water shrimps (Pandalus borealis)

LWT, 2020

 Users may download and print one copy of any publication from the public portal for the purpose... more  Users may download and print one copy of any publication from the public portal for the purpose of private study or research.  You may not further distribute the material or use it for any profit-making activity or commercial gain  You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

Research paper thumbnail of Control of α-Lactalbumin Aggregation by Modulation of Temperature and Concentration of Calcium and Cysteine

Journal of agricultural and food chemistry, Jan 2, 2018

The effect of free cysteine (in different concentrations) on the thermal aggregation of calcium-s... more The effect of free cysteine (in different concentrations) on the thermal aggregation of calcium-saturated (Ca-sat) and -depleted (Ca-dep) α-lactalbumin (α-LA) was investigated at 25, 50, and 70 °C. The temperatures chosen were below the denaturation temperature ( T) of Ca-dep and Ca-sat α-LA (25 °C), above the T of Ca-dep α-LA and below that of Ca-sat α-LA (50 °C), and above the T of Ca-sat α-LA (70 °C). Size-exclusion chromatography coupled to multiangle light scattering showed that no aggregation or only minor aggregation was obtained at the investigated temperatures for both Ca-dep and Ca-sat α-LA even at extended holding times. Aggregates of Ca-sat α-LA were larger than those developed for Ca-dep α-LA. The addition of cysteine, a low-molecular-mass free thiol, resulted in increased aggregation of both Ca-sat and Ca-dep α-LA. Comparisons of SDS-PAGE run under reducing and nonreducing conditions showed that the formed cross-links were primarily disulfide bonds, but Western blots a...

Research paper thumbnail of High pressure effects on myrosinase activity and glucosinolate preservation in seedlings of Brussels sprouts

Food chemistry, Jan 15, 2018

Combinations of pressure, temperature and time (100-600 MPa, 30-60 °C, 3-10 min) influence enzyme... more Combinations of pressure, temperature and time (100-600 MPa, 30-60 °C, 3-10 min) influence enzyme activity of the myrosinase-glucosinolate system. Seedlings of Brussels sprouts were used as a model, which constitutes a well-defined and homogenous sample matrix with simple cell structures. A response surface methodology approach was used to determine the combined effect of pressure level, temperature and time on glucosinolate concentration and myrosinase activity in Brussels sprouts seedlings. The effects on residual myrosinase activity and intact glucosinolate concentration differed according to combinations of pressure, time and temperature. The results showed that maximum inactivation of myrosinase and preservation of glucosinolate (85% of the untreated level) was obtained after HP treatment at 600 MPa, 60 °C, 10 min. The highest preservation of myrosinase activity compared to untreated seedlings was after HP at 100 MPa, 30 °C, 3 min and 10 min with low degree of cell permeabiliza...

Research paper thumbnail of Umami synergy as the scientific principle behind taste-pairing champagne and oysters

Scientific Reports, Nov 18, 2020

Research paper thumbnail of Protein changes in shell and epidermis of shrimp (Pandalus borealis) after maturation on ice or in salt

Research paper thumbnail of Effect of industrial process conditions of fava bean (Vicia faba L.) concentrates on physico-chemical and functional properties

Innovative Food Science & Emerging Technologies

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Formation of α-Dicarbonyls from Dairy Related Carbohydrates with and without Nα-Acetyl-l-Lysine during Incubation at 40 and 50 °C

Journal of Agricultural and Food Chemistry, 2019

-Dicarbonyls are reactive intermediates formed during Maillard reactions and carbohydrate degrad... more -Dicarbonyls are reactive intermediates formed during Maillard reactions and carbohydrate degradation. The formation of seven -dicarbonyls was characterized in solutions containing dairy related carbohydrates (galactose, glucose, lactose, and galacto-oligosaccharides (GOS)) during incubations at 40 ºC and 50 ºC with and without Nα-acetyl-L-lysine at pH 6.8 for up to 2 months. The concentrations of -dicarbonyls in samples of monosaccharides with Nα-acetyl-L-lysine were found to be: 3-deoxyglucosone (3-DG) > 3-deoxygalactosone (3-DGal) > glyoxal > glucosone, galactosone > methylglyoxal > diacetyl. The presence of Nα-acetyl-Llysine resulted in up to 100-fold higher concentrations of C6 -dicarbonyls, but lesser formation of glyoxal in the monosaccharide-containing models compared to what was observed in the absence of Nα-acetyl-L-lysine. Galactose incubated with Nα-acetyl-L-lysine generated the highest concentrations of 3-DGal (up to 130 µM), glyoxal (up to 100 µM) and methylglyoxal (up to 9 µM) compared to the other carbohydrates during incubation. Surprisingly, 3-DG (1500 µM) and 3-DGal (80 µM) were formed at levels of two orders of magnitude higher in solutions of GOS in the absence of Nα-acetyl-L-lysine as compared to the other carbohydrates at 40 ºC while GOS generated the lowest levels of glyoxal. GOS is widely used as an ingredient in various types of foods products, and it is therefore of importance to consider the risk of generating high levels of the reactive C6 -dicarbonyl, 3-DG in these types of products. This study contributes to the understanding of major -dicarbonyl formation as affected by the presence of primary amines in GOS, lactose, and galactose containing solutions under moderate heating in liquid foods.

Research paper thumbnail of Gastrophysical and chemical characterization of structural changes in cooked squid mantle

Journal of Food Science, 2021

Squid (Loligo forbesii and Loligo vulgaris) mantles were cooked by sous vide cooking using differ... more Squid (Loligo forbesii and Loligo vulgaris) mantles were cooked by sous vide cooking using different temperatures (46°C, 55°C, 77°C) and times (30 s, 2 min, 15 min, 1 h, 5 h, 24 h), including samples of raw tissue. Macroscopic textural properties were characterized by texture analysis (TA) conducted with Meullenet‐Owens razor shear blade and compared to analysis results from differential scanning calorimetry. The collagen content of raw tissues of squid was quantified as amount of total hydroxyproline using ultra‐high‐performance liquid chromatography. Structural changes were monitored by Raman spectroscopy and small‐angle X‐ray scattering and visualized by second harmonic generation microscopy. Collagen in the squid tissue was found to be highest in arms (4.3% of total protein), then fins (3.0%), and lowest in the mantle (1.5%), the content of the mantle being very low compared to that of other species of squid. Collagen was found to be the major protein responsible for cooking los...

Research paper thumbnail of The physical stability of plant-based drinks and the analysis methods thereof

Food Hydrocolloids, 2021

Plant-based drinks have increasingly become a regular product in the market. The range of raw mat... more Plant-based drinks have increasingly become a regular product in the market. The range of raw materials available creates an abundance of products with various properties. For product optimization purposes, it is imperative to fully characterize the product, especially in terms of its physical stability. This review aims to summarize the techniques currently available to characterize and understand the underlying factors describing the physical stability of plant-based drinks. The methods discussed range from general methods that have been widely used to specific fingerprinting spectroscopic techniques such as UV-VIS, FTIR, NIR, Raman, Fluorescence Spectroscopy, and NMR. The benefit and trade-off of each method is discussed in relation to its application for plant-based drink products. In addition, the classic colloid theory (the electric double layer) is mentioned to explain the separation phenomena which follow the discussion on available mechanisms to improve the system (electrostatic and steric stabilization mechanism).

Research paper thumbnail of Effects of high pressure and ohmic heating on shell loosening, thermal and structural properties of shrimp (Pandalus borealis)

Innovative Food Science & Emerging Technologies, 2019

This study aimed at understanding the effects of high pressure (HP) and ohmic heating (OH) on the... more This study aimed at understanding the effects of high pressure (HP) and ohmic heating (OH) on the peelability, the underlying mechanisms of HP-and OH-induced shell tightening, the thermal and structural properties of shrimp parts. HP improved the peelability of shrimp at low pressure level (<350 MPa) and short holding time (≤3 min) and the optimum condition for peeling was at 100 MPa for 3 min at 5°C. However, a higher pressure level (>350 MPa) led to a decrease in the peelability. High pressure at 600 MPa stabilized cuticular and epidermal collagen and formed new collagen-like structures by new linkages, which strengthened the muscle-shell connection and reduced the peelability. Shrimp meat induced from HP at 100 MPa and 600 MPa had minorly denatured myofibrillar proteins. OH as a blanching method did not significantly improve the peelability of shrimp at most of the studied conditions. Some extreme conditions (e.g. at 50°C) caused a markedly low peelability due to occurrence of collagen gelatinization. The gel formation from collagen-gelatin transformation under heating added strength to adherence of shell to epidermis and muscle, as a consequence, a difficult peeling was experienced. OH also denatured proteins in shrimp meat and caused loss of astaxanthin. Industrial relevance: The industrial processing of ready-to-eat shrimp involves the on-ice or in-brine maturation process which loosens the shrimp's shell from its meat, and therefore enable the mechanical peeling. However, the traditional maturation is time consuming (up to 4-5 days), inevitably leads to reduced quality of shrimp meat. This study shows the possibility of the application of HP at mild pressure levels to promote the shell loosening at short HP processing time (≤3 min). However, at more severe HP conditions could lead to the shell tightening which was caused by HP-induced stabilization of collagen in shell and epidermis. The study also shows that ohmic heating (<5 min) might not be a significant blanching method to support the maturation since OH had minor positive effect on shell loosening at 3 some OH conditions (e.g. 2 or 10% NaCl, 92V, and 30 or 35°C), but had a counter effect at most OH conditions especially at high temperature.

Research paper thumbnail of Squids of the North: Gastronomy and gastrophysics of Danish squid

International Journal of Gastronomy and Food Science, 2018

Several species of cephalopods, particularly squid, are present in Danish waters, but neither are... more Several species of cephalopods, particularly squid, are present in Danish waters, but neither are they fished commercially nor are they part of the Danes' traditional diet. However, if Danes can eat octopus, squid, and cuttlefish when visiting Southern Europe why do they hesitate to eat Danish cephalopods at home? Cephalopods are a nutritious, healthy, and sustainable source of seafood. Moreover, the populations of all species of cephalopods are globally on the rise in stark contrast to the dwindling traditional fisheries. Eating more of them is a way to a more insightful and sustainable use of the marine food resources. The challenge is how to prepare them into delicious 2 food and how to make the Danish population, the fishermen, and the retailers aware of their great potential and value as sustainable and delicious food. We have combined scientific gastrophysical investigations of various squid preparations with gastronomical design, innovation, development of recipes, and inventive product design to furnish a solid basis for spreading knowledge, appreciation of flavour, and a desire to consume Danish squid in Denmark.

Research paper thumbnail of Facilitating shrimp ( Pandalus borealis ) peeling by power ultrasound and proteolytic enzyme

Innovative Food Science & Emerging Technologies, 2018

The potential of power ultrasound (24-kHz frequency) as an individual treatment and in combinatio... more The potential of power ultrasound (24-kHz frequency) as an individual treatment and in combination with proteolytic enzyme to promote the shell-loosening of cold-water shrimp (Pandalus borealis) was investigated. Textural properties of shrimp were highly dependent on temperature control during the ultrasonic process (27.6-μm amplitude, 120 min duration and 0.9-s pulse), while the peelability of shrimp monitored as peeling work, meat yield and proportion of completely peeled shrimp were less dependent on the temperature. Increasing amplitude (0-46 µm) and time (0-45 min) of ultrasound prior to enzymatic maturation (0.5% Endocut-03L, 6 h, and 3 °C) increased the peelability of shrimp. The parallel combination of ultrasound and enzyme (18.4-μm amplitude, 0.9-s pulse, 0.5% Endocut-3L, 3-h and 4-h duration, and T ≤ 5 °C) considerably improved the shrimp peelability without detrimental effect on the texture and color of shrimp. Ultrasound was found to inactivate proteolytic enzyme in solution and to modify the structural properties of shrimp shells. From scanning electron micrographs (SEM), we proposed a mechanism for the ultrasound-enzyme-induced shell-loosening based on ultrasonic shell surface erosion and enzyme diffusion. Cavitation bubbles generated from sound waves pitted the surface of shrimp shell, generating pathways for enzyme diffusion into the muscle-shell attachment.

Research paper thumbnail of Morphology and Structure of Solid Lipid Nanoparticles Loaded with High Concentrations of β-Carotene

Journal of Agricultural and Food Chemistry, 2019

Research paper thumbnail of Proteomic and microscopic approaches in understanding mechanisms of shell-loosening of shrimp (Pandalus borealis) induced by high pressure and protease

Food Chemistry, 2019

Microstructure, protein profile, relationship between shrimp shell-loosening and protein, and mec... more Microstructure, protein profile, relationship between shrimp shell-loosening and protein, and mechanisms of shell-loosening after high pressure (HP) and enzyme treatment were investigated. The shell-loosening gap induced by an endoprotease with broad specificity (Endocut-03L) was much higher (53 μm) than that induced by HP at 100 MPa (HP100, 12 μm), followed by an endoprotease with high specificity (8 μm), and HP at 600 MPa (5 μm). The extent of protein changes in epidermis and shell corresponded with the shell-loosening gap. Thus, the gap could be predicted by the fold change of protein spots by a PLS model. Shell-loosening due to HP100 and Endocut-03L was mainly caused by physical and enzymatic degradation of high molecular-weight proteins in shell and epidermis and subsequent loss of degradation products, disrupting the structure of muscle-shell connection. However, HP100 was less effective than Endocut-03L due to its stabilizing effect on the shell collagen, lowering its shell-loosening effect.

Research paper thumbnail of Inhibition of Maillard Reactions by Replacing Galactose with Galacto-Oligosaccharides in Casein Model Systems

Journal of Agricultural and Food Chemistry, 2018

Lactose reduced dairy products are more prone to Maillard reactions due to the presence of reacti... more Lactose reduced dairy products are more prone to Maillard reactions due to the presence of reactive monosaccharides. Conventional β-galactosidases, which are used for lactose hydrolysis in lactose reduced dairy products, will lead to conversion of lactose into glucose and galactose, where especially galactose is very reactive during Maillard reactions. Some βgalactosidases have transgalactosylating activity, and will thus convert lactose into galactooligosaccharides (GOS) and hereby limit the release of galactose. The aim of this study was to investigate the extent of participation of GOS in Maillard reactions in comparison to lactose, a 50:50 mixture of glucose and galactose, and galactose exclusively in sodium caseinate based milk-like model systems heated at 130 o C and 75 o C at pH 6.8. The GOS system exhibited reduced loss of free amino groups, accumulated less furosine and less of the following advanced glycation end products (AGEs): N -carboxyethyl lysine (CEL), methylglyoxalderived hydroimidazolone isomers (MG-H), glyoxal-derived lysine dimer (GOLD), and methylglyoxal-derived lysine dimer (MOLD), and also developed less browning compared to monosaccharide models. However, the GOS-caseinate system accumulated more 3deoxyglucosone and 3-deoxygalactosone, which resulted in higher concentrations of 5-(hydroxymethyl)furfural and pyrraline. The results indicated that GOS overall participate less readily in Maillard reactions than the monosaccharides investigated, but were more prone to degradation to C6 -dicarbonyls species. Finally, relationship analysis indicated that C6 dicarbonyls seemed to primarily increase concentrations of 5-(hydroxymethyl)furfural instead of AGEs. Our results suggest that conversion of lactose into GOS instead of monosaccharides in milk by transgalactosylating β-galactosidases could be a useful strategy for production of lactose-free milk for people with lactose-intolerance.

Research paper thumbnail of A Comprehensive Approach to Assess Feathermeal as an Alternative Protein Source in Aquafeed

Journal of Agricultural and Food Chemistry, 2017

The effect of partially replacing fishmeal in aquafeed with feathermeal (FTH) at three levels (0%... more The effect of partially replacing fishmeal in aquafeed with feathermeal (FTH) at three levels (0%: FTH0, 8%: FTH8, 24%: FTH24) and two extrusion temperatures (100 and 130 °C) were evaluated in rainbow trout (Oncorhynchus mykiss) with respect to growth 4 performance, metabolism response, and oxidative status of the feed proteins. Multivariate 5 data analyses revealed that FTH24 correlated positively with high levels of: oxidation products, amino acids (AA) racemization, glucogenic AAs level in liver, feed intake (FI), specific growth rate (SGR), and feed conversion ratio (FCR); and low AAs digestibility. Both FI and SGR were significantly increased when 8 and 24% feathermeal was included in the feed extruded at 100 °C, while there was a negative effect on FCR in fish fed FTH24. In conclusion, higher oxidation levels in FTH24 may give rise to metabolic alterations while lower levels of FTH may be considered as fishmeal substitute in aquafeed for rainbow trout.

Research paper thumbnail of Casein micelle dissociation in skim milk during high-pressure treatment: Effects of pressure, pH, and temperature

Journal of Dairy Science, 2010

The effect of pH (from 5.5 to 7.5) and temperature (from 5 to 40°C) on the turbidity of reconstit... more The effect of pH (from 5.5 to 7.5) and temperature (from 5 to 40°C) on the turbidity of reconstituted skim milk powder was investigated at ambient pressure and in situ under pressure (up to 500 MPa) by measurement of light scattering. High-pressure treatment reduced the turbidity of milk for all combinations of pH and temperature due to micelle dissociation. The turbidity profiles had a characteristic sigmoidal shape in which almost no effect on turbidity was observed at low pressures (100 MPa), followed by a stronger pressure dependency over a pressure range of 150 MPa during which turbidity decreased extremely. From the turbidity profiles, the threshold pressure for disruption of micelle integrity was determined and ranged from 150 MPa at low pH to 350-400 MPa at high pH. The threshold pressure diagram clearly showed a relationship between the barostability of casein micelles and pH, whereas almost no effect of temperature was shown. This remarkable pH effect was a consequence of pressure-induced changes in the electrostatic interactions between colloidal calcium phosphate and the caseins responsible for maintaining micellar structure and was explained by a shift in the calcium phosphate balance in the micelle-serum system. Accordingly, a mechanism for high pressure-induced disruption of micelle integrity is suggested in which the state of calcium plays a crucial role in the micelle dissociation process.

Research paper thumbnail of Riboflavin-sensitized photooxidation of isohumulones and derivatives

Photochemical & Photobiological Sciences, 2004

Isohumulones, the bitter principles in beer, are decomposed by light-induced reactions, thereby a... more Isohumulones, the bitter principles in beer, are decomposed by light-induced reactions, thereby adversely affecting beer quality. Upon absorption of visible light, riboflavin is excited and interacts with isohumulones, as well as with oxidized and reduced derivatives thereof. Reaction kinetics were investigated by laser flash photolysis at 355 nm and at 440 nm, and analysis of kinetic data afforded detailed insights into the reaction mechanism.

Research paper thumbnail of Stopped-flow kinetic studies of the reaction of barley α-amylase/subtilisin inhibitor and the high pI barley α-amylase

FEBS Letters, 1995

The interaction of a-amylase/subtilisin inhibitor (BASI) from barley seeds and the high pI barley... more The interaction of a-amylase/subtilisin inhibitor (BASI) from barley seeds and the high pI barley a-amylase (AMY2) de novo synthesized during seed germination, has been studied at pH 8.0, 25°C, using stopped-flow fluorescence spectroscopy, equilibrium fluorescence titration and kinetic analysis of the displacement of BASI from the BASI-AMY2 complex by the substrate blue starch. The results are in accordance with a two-step reaction model: xl 42 BASI + AMY2 ~ BASI-AMY2 ~ BASl-AMY2* /;-2 The resulting values of the kinetic parameters were: k21K l = (1.0 + 0.2) × 106 M-1 "s-i,/(i = 0.4 + 0.21 mM, k 2-320 + 150 s-1, k_ 2 = (7.2 + 0.6) × 10-Ss-1, and the overall dissociation constant Kd = (0.7 + 0.1) × 10-1° M. BASI thus is best characterized as a fast reacting, tight-binding inhibitor of AMY2.

Research paper thumbnail of Two Statistical Tools for Assessing Functionality and Protein Characteristics of Different Fava Bean (Vicia faba L.) Ingredients

Foods, 2021

Fava bean (Vicia faba L.) is a promising source of proteins that can be potentially used as nutri... more Fava bean (Vicia faba L.) is a promising source of proteins that can be potentially used as nutritional and/or functional agents for industrial food applications. Fava ingredients are industrially produced, modified, and utilized for food applications. Their processing conditions influence physico-chemical protein properties that further impact ingredient functionality. To design a functionally suitable ingredient, an understanding of the interrelationships between different properties is essential. Hence, this work aimed to assess two statistical analytical tools, Pearson’s correlation and Principal Component Analysis (PCA), for investigating the role of the process conditions of fava ingredients on their functional and protein properties. Fava concentrates were processed by pH (2, 4, 6.4 and 11), temperature (55, 75 and 95 ∘C) and treatment duration (30 and 360 min) into different modified ingredients. These were utilized under two application conditions (pH 4 and 7), and their fo...

Research paper thumbnail of Effect of ice maturation, freezing and heat treatment on the peelability and quality of cold water shrimps (Pandalus borealis)

LWT, 2020

 Users may download and print one copy of any publication from the public portal for the purpose... more  Users may download and print one copy of any publication from the public portal for the purpose of private study or research.  You may not further distribute the material or use it for any profit-making activity or commercial gain  You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

Research paper thumbnail of Control of α-Lactalbumin Aggregation by Modulation of Temperature and Concentration of Calcium and Cysteine

Journal of agricultural and food chemistry, Jan 2, 2018

The effect of free cysteine (in different concentrations) on the thermal aggregation of calcium-s... more The effect of free cysteine (in different concentrations) on the thermal aggregation of calcium-saturated (Ca-sat) and -depleted (Ca-dep) α-lactalbumin (α-LA) was investigated at 25, 50, and 70 °C. The temperatures chosen were below the denaturation temperature ( T) of Ca-dep and Ca-sat α-LA (25 °C), above the T of Ca-dep α-LA and below that of Ca-sat α-LA (50 °C), and above the T of Ca-sat α-LA (70 °C). Size-exclusion chromatography coupled to multiangle light scattering showed that no aggregation or only minor aggregation was obtained at the investigated temperatures for both Ca-dep and Ca-sat α-LA even at extended holding times. Aggregates of Ca-sat α-LA were larger than those developed for Ca-dep α-LA. The addition of cysteine, a low-molecular-mass free thiol, resulted in increased aggregation of both Ca-sat and Ca-dep α-LA. Comparisons of SDS-PAGE run under reducing and nonreducing conditions showed that the formed cross-links were primarily disulfide bonds, but Western blots a...

Research paper thumbnail of High pressure effects on myrosinase activity and glucosinolate preservation in seedlings of Brussels sprouts

Food chemistry, Jan 15, 2018

Combinations of pressure, temperature and time (100-600 MPa, 30-60 °C, 3-10 min) influence enzyme... more Combinations of pressure, temperature and time (100-600 MPa, 30-60 °C, 3-10 min) influence enzyme activity of the myrosinase-glucosinolate system. Seedlings of Brussels sprouts were used as a model, which constitutes a well-defined and homogenous sample matrix with simple cell structures. A response surface methodology approach was used to determine the combined effect of pressure level, temperature and time on glucosinolate concentration and myrosinase activity in Brussels sprouts seedlings. The effects on residual myrosinase activity and intact glucosinolate concentration differed according to combinations of pressure, time and temperature. The results showed that maximum inactivation of myrosinase and preservation of glucosinolate (85% of the untreated level) was obtained after HP treatment at 600 MPa, 60 °C, 10 min. The highest preservation of myrosinase activity compared to untreated seedlings was after HP at 100 MPa, 30 °C, 3 min and 10 min with low degree of cell permeabiliza...