Characterization of protein-enriched yogurt and its effects on the lean body weight gain and electrical activity in skeletal muscle of physically active individuals (original) (raw)
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Impact of composition and texture of protein- added yogurts on oral activity
Understanding how oral processing is altered in response to changes in the composition and mechanical properties of food provides useful information to design food with improved satiating capacity which is largely influenced by oral exposure. In turn, this information deepens the knowledge about the physiology of texture perception. Six yogurts were formulated with different amounts of protein and protein sources and addition of apple cubes: control (C), extra skimmed milk powder-added (MP), whey protein isolate-added (WPI), and whey protein microgels-added (WPM). In addition, MP was also added with maltodextrin (MPMD) and with fresh apple cubes (MPF). Activities of masseter, anterior temporalis and anterior digastric muscles during oral processing of each sample were recorded (electromyography), and jaw movement amplitudes in three dimensions were determined (jaw tracking system). The jaw muscle activities were highly dependent on the type of yogurt. Addition of apple cubes (MPF) almost doubled the oral processing time, number of chews, and muscle activity of all samples. MP and MPMD required similar but lower values of oral processing than MPF attributed to their reinforced network of milk protein. The lowest values were found for WPI, C and WPM, indicating a weaker, more fluid material. These behavioral results, which clearly differentiate the samples, are discussed in connection to the rheological and sensory properties of the yogurts. This study suggests that adding apple cubes significantly alters the oral processing pattern, such that they may be a more effective way of increasing the oral processing time (time exposure) compared to more subtle changes in the protein amount or source. Nevertheless, changes in the protein amount and source also affected, although to a lesser extent, the behavioral, rheological, and sensory properties of yogurt.
Frontiers in Nutrition, 2019
Milk and/or whey protein plus resistance exercise (RT) increase strength and muscle size, and optimize body composition in adult males and females. Greek yogurt (GY) contains similar muscle-supporting nutrients as milk yet it is different in several ways including being a semi-solid food, containing bacterial cultures and having a higher protein content (mostly casein) per serving. GY has yet to be investigated in the context of a RT program. The purpose of this study was to assess the effects of GY consumption plus RT on strength, muscle thickness and body composition in lean, untrained, university-aged males. Thirty untrained, university-aged (20.6 ± 2.2 years) males were randomized to 2 groups (n = 15/group): fat-free, plain GY or a Placebo Pudding (PP; isoenergetic carbohydrate-based pudding) and underwent a combined RT/plyometric training program 3 days/week for 12 weeks. They consumed either GY (20 g protein/dose) or PP (0 g protein/dose) daily, 3 times on training days and 2 times on non-training days. After 12 weeks, both groups significantly increased strength, muscle thickness and fat-free mass (FFM) (p < 0.05). The GY group gained more total strength (GY; 98 ± 37 kg, PP; 57 ± 15 kg), more biceps brachii muscular thickness (GY; 0.46 ± 0.3 cm, PP; 0.12 ± 0.2 cm), more FFM (GY; 2.4 ± 1.5 kg, PP; 1.3 ± 1.3 kg), and reduced % body fat (GY; −1.1 ± 2.2%, PP; 0.1 ± 2.6%) than PP group (p < 0.05 expressed as absolute change). Thus, consumption of GY during a training program resulted in improved strength, muscle thickness and body composition over a carbohydrate-based placebo. Given the results of our study, the general benefits of consuming GY and its distinctiveness from milk, GY can be a plausible, post-exercise, nutrient-rich alternative for positive strength, muscle, and body composition adaptations.
How is an ideal satiating yogurt described? A case study with added-protein yogurts
Protein is recognized as the macronutrient with the highest satiating ability. Yogurt can be an excellent basis for designing satiating food as it is protein-based food product. Five different set-type yogurts were formulated by adding extra skim milk powder (MP), whey protein concentrate (WPC), calcium caseinate (CAS) or a blend of whey protein concentrate with calcium caseinate (CAS-WPC). A control yogurt without extra protein content was also prepared. Differences in sensory perceptions (through CATA questions) were related to the consumers' expected satiating ability and liking scores (of several modalities). In addition, an "Ideal satiating yogurt" was included in the CATA question to perform a penalty analysis to show potential directions for yogurt reformulation and to relate sensory and non-sensory yogurt characteristics to satiating capacity.
Food Science & Nutrition, 2014
Concentrated/Greek yogurt or Labneh is a semisolid food produced from yogurt by eliminating part of its water and water-soluble compounds. Today's world is geared toward the production of lower fat foods without compromising the texture and flavor of these products. The objective of this study was to characterize the physicochemical and sensory properties of bovine, caprine, and ovine Labneh with different fat levels. Bovine, caprine, and ovine milks were used to produce two batches of full-fat (~10%), reduced-fat (~5%), and low-fat (<1%) concentrated yogurt samples. Chemical analyses of fat, moisture, protein, ash, syneresis, acidity, pH, sodium, magnesium, and calcium contents were conducted. Instrumental texture analysis using the back extrusion method was applied. Quantitative descriptive sensory analysis was used to profile samples by 11 trained panelists and the acceptability of samples was assessed by 47 panelists. Type of milk significantly affected (P < 0.001) all chemical attributes except moisture and nitrogen-free extract, and fat level significantly impacted moisture, fat, protein, ash, acidity, and magnesium contents of Labneh. Type of milk significantly affected apparent modulus, hardness, hardness work done, and adhesive force, whereas fat level significantly affected hardness. Type of milk significantly affected the sensory attributes of syneresis, compactness, goaty odor and flavor, rate of flow, color, shininess, bitter flavor, denseness, melting rate, and spreadability, whereas fat level affected only color, denseness, and melting rate. Type of milk had a significant effect on overall acceptability and acceptability of flavor and texture.
Physical properties of yogurt fortified with various commercial whey protein concentrates
Journal of the Science of Food and Agriculture, 2005
The effects of whey protein concentrates on physical and rheological properties of yogurt were studied. Five commercial whey protein concentrates (340 g kg −1 protein nominal) were used to fortify milk to 45 g protein kg −1 . Fermentation was performed with two different starters (ropy and non-ropy). Resulting yogurts were compared with a control yogurt enriched with skim milk powder. The waterholding capacity of the yogurt fortified with skim milk powder was 500 g kg −1 and ranged from 600 to 638 g kg −1 when fortified with whey protein concentrates. Significant rheological differences have been noticed between the yogurts fortified with different whey protein concentrates, independent of the starter used. Three whey protein concentrates generated yogurts with a behavior similar to the control. The two others produced yogurt with lower firmness (15 g compared with 17 g), lower Brookfield viscosity (6 Pa s compared with 9 Pa s), lower yield stress (2 Pa compared with 4 Pa), lower complex viscosity (13 Pa s compared with 26 Pa s), and lower apparent viscosity (0.4 Pa s compared with 1 Pa s) than the control, respectively. The yogurts with the lowest firmness and viscosity were produced with concentrates which contained the highest amount of non-protein nitrogen fraction (160 g kg −1 versus 126 g kg −1 of the total nitrogen), and the highest amount of denaturation of the whey protein (262 versus 200 g kg −1 of the total nitrogen).
Designing added-protein yogurts: Relationship between in vitro digestion behavior and structure
Food Hydrocolloids, 2017
Increasing the protein content of a food is an effective way to deliver enhanced satiating signals to the consumer. Protein structures are related to their breakdown properties under gastric conditions and understanding their in vitro proteolysis could provide valuable information on their contribution to satiating ability. Four different yogurts were formulated with double the amount of protein by adding extra skimmed milk powder (MP), whey protein concentrate (WPC), calcium caseinate (CAS) or a blend of whey protein concentrate and calcium caseinate (MIX). Their rheological behavior and light microscopy and SDS-PAGE data were analyzed at different times of oral plus gastric in vitro digestion (0, 30, 60 and 120 min). The yogurts with added whey protein (WPC and MIX) maintained high consistency index values throughout in vitro digestion, which is related to increased gastric distension and to an extended feeling of fullness. In addition, the rapid gastric emptying of whey proteins in a more unaltered form than casein may result in a stronger increase in postprandial plasma amino acid concentration, increasing the satiating signals. Consequently, adding whey protein to the formulation of yogurts can enhance satiety, despite processing steps such as thermal treatment and fermentation.
Frontiers in Nutrition, 2022
Upcoming developments are attracting attention to both high-protein and probiotics supplementation for the sports community to promote good health and exercise performance. This study aimed at the production of high-protein concentrated pro-yogurt (Pro-WPI) enriched with 10 and 20% whey protein isolate (WPI) and investigation of the response of daily consumption on anthropometric, hematology parameters, and athletic performance in parallel with safety consideration assessment. Twenty-four athletes (19.6 ± 1.45 years; 175.96 ± 5.24 cm; 73.16 ± 8.65 kg) were participated in a randomized placebo-control study. They consumed Pro-WPI products with 10 (T1) and 20% (T2) WPI for treatments G1 (Pro-WPI30) and G2 (Pro-WPI60), respectively, 3 times per day/5 days per week/9 weeks. The taste of Pro-WPI products was sour and cheesy, while mouthfeel was described as soft and thick because of the increased protein content in T1 and T2 (14.15 and 22.58%). The hemoglobin of the athletes increased si...
QUALITY ATTRIBUTES OF PROTEIN FORTIFIED YOGHURT
J. Food and Dairy Sci., Mansoura Univ., Vol. 6 (4): 227 -241., 2015
The aim of this study was to evaluate the quality attributes of yoghurt made from cow's milk (3.6%fat and 3.37% protein) fortified with different levels of milk protein (0.5, 1.0 or 1.5%) as skim milk powder (SMP), sodium caseinate (NaCn) and dried whey protein concentrate (WPC); or ultrafiltrated (UF) to similar protein levels. The results indicated that titratable acidity (TA), acetaldehyde (AC) and diacetyl (DA) contents as well as the firmness (Fr), as inversely indicated from the penetration value, consistency coefficient (CC) and yield stress (YS) of yoghurt raised as the protein fortification level increased, by which the reduction in pH values were delayed. SMP-fortified yoghurt had the highest contents of TA, AC and DA and the lowest pH value, followed by WPC, UF and NaCn, which caused the greatest Fr and YS followed by UF. Proportional increases in TA and all rheological parameters were determined, while pH value decreased continuously until the end of SP. The increment in the AC and DA contents retreated after the 7 th and 14 th day respectively. Gradual increment in Streptococcus. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus counts associated with protein elevation level was determined. SMP in yoghurt promoted the highest viability conditions for both strains followed by W PC, UF and NaCn. The duration of storage period (SP) for 21 days led to gradual reduction in counts of both strains. In conclusion, the yoghurt with increased 1.0% protein by UF, attained the highest total sensory scores, and was kept with stable sensory quality until the 14 th day and stilled acceptable until the end of storage period.
Food and Bioprocess Technology, 2013
The production and incorporation of liquid whey protein concentrates (LWPCs) in fresh cheese and set yogurt is proposed as a solution for immediate reutilization of whey produced by small-and medium-scale dairy plants avoiding expensive processing steps (e.g., evaporation and drying) for the recovery of this by-product. Accordingly, the incorporation of LWPCs in such products was performed in order to compare the functional and sensorial properties of modified products with the conventional ones. The use of LWPC in fresh cheese increased water-holding capacity as well as product stability during storage. Fresh cheese hardness, chewiness, and gumminess decreased during storage in a more pronounced way in products with LWPC. The fat content influences significantly all the physicochemical properties tested in set yogurts. Incorporating LWPC in set yogurts does not produce appreciable differences in the visual properties when considering products with medium-fat content, but these differences become significant for full-fat yogurts. Adhesiveness and springiness were not significantly affected with storage time or by the amount of LWPC incorporated for medium-fat yogurts. Higher values of hardness and gumminess were obtained for full-fat yogurts, but these parameters decreased with LWPC incorporation. Syneresis was reduced using LWPC but increased with storage time. During storage, viscosity differences between LWPC incorporated yogurts and the conventional ones were only maintained in the case of creamy yogurts. The sensory panel detected differences between conventional and modified products in the case of fresh cheeses but no significative differences were detected between yogurts. LWPCs can be a good alternative to conventional dry products used in fresh cheese and set yogurt manufacture since their utilization reduces milk consumption and allows for the increase in total solids content. Additionally, their incorporation in milk originates end products with attractive physicochemical and sensorial characteristics at lower production costs.
Protein is the most effective food macronutrient providing a satiating effect. Thus, formulating dairy foods with increased protein contents can help to modulate food intake. Oral perception cues also contribute an increased perception of satiating capacity when the oral residence time and handling are longer and more laborious. In the present work, yogurts were prepared with double skimmed milk powder (MP) and whey protein (WP), as well as a control (C) without extra protein. Three more samples were prepared by adding 2% of a physically modified starch to each (CS, MPS and WPS, respectively), in order to increase the consistency and impart creaminess. Rheological tests were used to characterize the flow and viscoelastic properties of the samples before and after saliva treatment, and their microstructure was observed. Finally the differences in sensory perceptions elicited by the samples were related to consumers' expected satiating capacity and liking scores. Before in vitro oral digestion, MP showed denser areas than C; in WP, two protein networks could be distinguished. In the samples with added starch, starch granules were embedded in the protein networks. After in vitro oral digestion the protein tended to aggregate; the starch granules maintained their structure indicating that they were not broken down by the saliva. These observations were related to the samples' rheological behavior. The sensory graininess, lumpiness and grittiness detected in the WP samples could be linked to the aggregation of whey protein and the formation of two different protein networks. All the added-starch samples elicited creamier and denser sensations than their counterparts without starch. MP with starch was scored as the most satiating and best-liked yogurt sample.