Investigation of drying conditions on bioactive compounds, lipid oxidation, and enzyme activity of Oregon hazelnuts ( Corylus avellana L.) (original) (raw)
Related papers
2019
The aim of the work was to assess the effect of different drying conditions and storage time on raw unshelled Tonda Gentile Romana hazelnuts (harvest 2017). Drying was conducted with a laboratory desiccator at 20, 30, and 40 °C, applying two air circulation velocity until the moisture content of samples was lower than 6%. The oxidation state of the lipid fraction and volatile profile of hazelnuts were studied during 15 months of storage. In addition, sensory analysis was performed among samples.
2018
Drying is one of the most important stages of hazelnut processing and its optimization improves the quality of the final product. The quality of hazelnut is dependent on chemical and organoleptic characteristics of fruit that is affected in the drying process. In present research, samples of Gerd cultivar of hazelnut (Corylus avellana) were dried in shelled and in-shell forms using a laboratory dryer in single-layered form, in three temperatures of 40, 50 and 60°C and 1 m/s air velocity, and stored for six months. The time and energy required for drying and qualitative changes of hazelnut (oil content, protein content, acidity content and peroxide value of oil) were evaluated. The results showed that the hazelnuts dried under 60°C required the lowest time and energy for drying and the in-shell hazelnuts dried under this temperature (60°C) had the lowest acidity compared to other treatments. In addition, temperature had a significant effect on the qualitative traits of hazelnut. The...
Turkish Journal of Food and Agriculture Sciences
The main aim of this study was to evaluate the effect of nut sizes and drying methods on the sensory attributes of hazelnut cultivars (Corylus avellana L. cvs. Çakıldak, Palaz and Tombul) during the storage. Shelled hazelnut were dried under sun, shadow at room conditions and cold dried at 2 °C and 7 °C and stored at 20±5 °C and 80±5 % relative humidity. Evaluation of sensory attributes was carried out quarterly (harvest, 3, 6, and 9 months). In the Çakıldak cultivar (in 16 mm size), the odor of cold-dried hazelnuts at 2°C was higher than other drying methods in the last two measurements. It was observed that shadow-dried hazelnuts and at 7°C cold, dried hazelnuts had lower rancidity. No significant effect of drying methods was observed on the cultivars' flavor, firmness and color. As a result, it is revealed that drying methods have an effect on the rancidity in hazelnut kernels during storage.
Drying Kinetics and Moisture Transfer Parameters of Hazelnut
Journal of Food Processing and Preservation, 2011
In this experimental study, drying kinetics, sorption isotherms and mass transfer parameters (mainly the diffusion coefficient and hm) of hazelnut are investigated under various drying air conditions. Experiments were conducted in a lab-scale convective drier under the following drying conditions: temperatures at 25C, 35C, 45C and 55C; velocities at 0.3, 0.6 and 0.9 m/s; relative humidity values at 20%, 40%, 60% and 80%. Initially, sorption isotherms of the dried hazelnut are determined for different temperatures and equilibrium relative humidity values. Then, the drying characteristics of hazelnut are determined for various values of drying air parameters tested. In addition, the mass transfer parameters (i.e., Bi, moisture diffusion coefficient and hm) of hazelnut were evaluated using a correlation. The Bi numbers were in the range 0.4216-1.4806 and moisture diffusion coefficient and hms in the range from 0.7056 ¥ 10-9 to 3.2933 ¥ 10-9 and from 1.2401 ¥ 10-7 to 1.7361 ¥ 10-7 m/s, respectively. PRACTICAL APPLICATIONS Turkey is the largest hazelnut-producing country, providing most of world hazelnut production. Supplying the market with the best product available is always critical. Therefore, ensuring better harvesting and processing conditions of hazelnut attracts a great deal of research interest. To prevent field losses by unfavorable weather conditions, there is a tendency to harvest hazelnuts at moisture contents above safe storage levels. In this regard, drying seems to be necessary.
Effect of Different Storage Conditions on Hazelnut Quality
The aim of this study was to evaluate the effect of different storage conditions on the quality of the hazelnut cultivar 'Tonda Gentile delle Langhe'. The traditional method of in-shell nut storage, in storage room at ambient temperature, was compared with preservation of shelled nuts in refrigerated room at 4°C and 55% RH with or without modified atmosphere (1% oxygen, 99% nitrogen). In order to evaluate nut quality, the following parameters were considered: humidity, lipid content, total phenolic content and antioxidant capacity of the seed; acidity and peroxide value of the oil. The results showed that the acidity and the peroxide value were the most discriminating parameters. After one year of storage, the acidity of hazelnuts stored at ambient temperature (0.47% oleic acid) was higher than the value considered the acceptable limit after storage (0.40% oleic acid), while the storage at low temperature permitted to maintain a low level of acidity and lipid oxidation, with the best performance in modified atmosphere (0.13% of oleic acid and 0.11 mEq O 2 /kg). In conclusion, the in-shell storage of hazelnuts at ambient temperature was able to preserve the kernel below threshold limits of acidity and oxidative degradation up to a period of 8 months; the application of refrigeration was necessary to maintain a high quality up to one year. The use of modified atmosphere is recommended for a longer period of storage.
Postharvest Biology and Technology, 2013
(AAM) is copyrighted and published by Elsevier. It is posted here by agreement between Elsevier and the University of Turin. Changes resulting from the publishing process-such as editing, corrections, structural formatting, and other quality control mechanisms-may not be reflected in this version of the text. The definitive version of the text was subsequently published in Effect of storage conditions on chemical and physical characteristics of hazelnut (Corylus avellana L.
Storage Hazelnuts: Effect on Aromatic Profile and Sensory Attributes
Acta Horticulturae, 2009
The hazelnuts quality was studied during and after the storage in selected maintenance conditions. Hazelnuts of 'Tonda Gentile Romana' cultivar and Turkish provenance were stored with and without oxygen presence (air, vacuum with or without nitrogen saturation packaging) at two different temperatures (4-20°C). During storage, the quality was monitored by assessment of the peroxides value, acidity level, sensory analysis, total phenolic compounds content and hexanal content. It was observed that after nine months storage period, the trials without oxygen were in better condition to preserve the hazelnuts from oxidative decline. The best analytical parameter to identify the oxidative state of hazelnuts was the hexanal content conducted through the SPME/GC method, and the decrease in amount of polyphenolic compounds. INTRODUCTION A study was carried out on fresh and stored, raw and roasted hazelnuts ('Tonda Gentile Romana' and 'Turkish') during storage under different conditions (room temperature, 4°C and vacuum, with and without nitrogen saturation) mainly on the volatile compounds, chemical parameters and sensory characteristics for monitoring shelf-life and the oxidation state of hazelnuts. The hazelnuts, as with most other foods with high fat content, are susceptible to lipid enzymatic or non-enzymatic oxidation. The primary oxidation products from unsaturated fatty acids, are the hydroperoxides, highly reactive compounds, that decompose rapidly, yielding a complex mixture of non-volatile and volatile compounds such as hydrocarbons (ethane, pentane), aldehydes (pentanal, hexanal, hexenal, 2-octenal, 2-nonenal) and ketones, which affect the overall quality of the product. Aldehydes are particularly important in relation to flavour alteration and from a toxicological perspective (Frankel, 1980,1982,1993). Extended storage of raw and roasted hazelnuts increases the production of fat oxidation off-flavours. The major product of fat oxidation that increases in content during storage is hexanal, more researchers have proposed it as an indicator of fat oxidation rather than the traditional oxidation indicators which are acidity or peroxide values (P.V.). The main aim of our work was to identify for hazelnuts good shelf-life indicators of the oxidative condition of the products during storage. MATERIALS AND METHODS Samples of hazelnuts of two different provenences, Italy, Latium Viterbo area, var. 'Tonda Gentile Romana' (TGR) and Turkish, both raw (Natural N) and roasted (R) were used. The hazelnuts were stored at 4°C (r) or room temperature 20-22°C (a), in open air (a) or into multilayer bags under vacuum. More specifically, the specimens were packed into 10 kg-multilayer bags that were under-vacuum sealed (V) or alternatively into 1 mg-multilayer bags, that were previously flushed with nitrogen to remove all the air and finally under-vacuum sealed (NV). All specimens were scheduled to be stored for 9 months, from February-November 2007 and to be sampled after 2, 4, 7 and 9 months (Fig. 1). All samples were provided by Stelliferi & Itavex (Caprarola-VT).
Journal of Food Quality, 2004
Hazelnuts ( Corylus avellana L.) were collected from three different cultivars (Tombul, Palaz and Kalınkara) at the harvest season of 1996. The dried nuts were stored shelled and unshelled in polyethylene bags at 21C and 60-65% relative humidity for 12 months. During storage, the total fat content increased, the palmitic and oleic acid content of the oil increased, linoleic acid, ranged from 12.41 to 10.35%. No significant differences were found for other fatty acids during storage. The effect of storage of shelled and unshelled hazelnuts on the total fat content was significant.
Effect of MW-assisted roasting on nutritional and chemical properties of hazelnuts
Food & Nutrition Research, 2015
In order to enhance the flavor, texture, color, and appearance of hazelnuts, they are roasted during postharvest processing. In this study, raw hazelnuts (Corylus avellana L.) were roasted using microwave (MW) and MWassisted hot air methods under various roasting conditions. The hazelnuts roasted were then examined to determine the percent DPPH radical scavenging activity, antioxidant capacity, total phenolic content, resistant starch, non-resistant starch, total starch, and protein concentration. The roasting experiments were done using a completely randomized factorial arrangement of two roasting types by three roasting times (9, 15, and 21 min) by three roasting temperatures (70, 90, and 1108C) using three replications within each experiment. These roasting methods were found to yield significant differences in antioxidant capacity, total phenolic content, resistant starch, non-resistant starch, and protein concentration between MW and MW-assisted hot air roasting processes, while no difference was found in percent DPPH radical scavenging activity and total starch. The results obtained may be of great importance to the food research community and industrial hazelnut roasting technologies.