Determination of water activity corresponding to the proper quality of peanut kernels

Abstract

Oxidative indices including peroxide value (PV), para‐anisidine value (p‐AnV), and extinction coefficients K232 and K268, instrumental texture attributes (hardness and chewiness) and colour parameters (L, a, b, and total colour difference) were measured to find the proper water activity (aw) corresponding to the proper quality of peanut kernels during a certain period of storage. The highest and lowest oxidation rates were recorded for the samples kept in aw values of 0.11 and 0.32–0.43, respectively. The stress required to obtain 25% deformation (MPa) decreased significantly (p < .05) with the increasing moisture content of the samples. In summary, less hardness, colour properties closer to fresh kernels as well as slower oxidation progress were measured for the samples stored at a higher aw, especially those stored at 0.32–0.43 at 40°C (equivalent to 0.33–0.43 at 25°C). Practical applications Peanuts (Arachis hypogaea) are grown in tropical, subtropical, and warm temperate climates in more than 70 countries. Like other nuts, peanuts are being consumed as snack foods after roasting or are used as chopped ingredients in cereal bars, confectionery, and breakfast cereals. Therefore, controlling peanut storage conditions (specially aw and temperature) should be considered before use for different purposes. In this study, color, texture, and oxidative changes of peanuts grown in northern Iran, as affected by aw were investigated in order to determine the best aw corresponding to proper quality during storage before being used in various applications at industrial scales.

Encapsulation of EPA and DHA concentrate from Kilka fish oil by milk proteins and evaluation of its oxidative stability

“…It is believed that different factors including oxidation reaction, loss or reduction in antioxidant compounds (Guine et al 2015) and Millard reaction (Christopoulos and Tsantili 2011) are predominant factors for higher redness (a-value) and lower lightness (Lvalue) in low water containing foods during storage. Qualitative development of red-golden colour for peanuts (Ghorbani and Hosseini 2017) and corn flour (Lopez-Duarte and Vidal-Quintanar 2009) kept in temperatures higher than 40°C was previously reported as confirmed by the present work. In line with the results of chemical tests (Table 2), less colour changes were observed for the samples containing glyceride product when a prolonged ultrasound time (3 min) was associated with the different powers (180 or 380 W) as compared to those treated by a short time (1 min).…”

“…Evaluation of colour parameters (R, G, B) for the powders stored in a w = 0.43 at 40°C for 12 days was carried out using image processing of sample images taken by a scanner (Hewelett Packard, Scanjet G3110, USA) as described by Ghorbani and Hosseini (2017). The scanner resolution was set at 1240 9 1240 pixels (1200 dpi).…”

Extending the shelf-life of sponge cake by an optimized level of jujube fruit flour determined using custom mixture design

“…Formation of conjugated trienoic acids was not affected ( pW0.05) by baking procedure, JF level and their interactions, while the rest of the parameters were significantly ( po0.05) influenced by at least two terms, confirming the important effect of added JF and baking temperature on both oxidative indices and textural properties of stored cake (Table III). In line with the literature (Pegg, 2005;Ghorbani and Hosseini, 2017;Hosseini, Ghorbani, Jafari and Sadeghi Mahoonak, 2019), the trend of changes in CTV was different from the other oxidative parameters. In fact, in fatty acids with three or more double bonds, CD moieties are formed at the earlier steps of the oxidation reaction, followed by the CT moiety (Pegg, 2005).…”

“…The changes in oxidation indices were evaluated to determine the effect of JF on progress of oxidation reactions during storage. Therefore, at given intervals (1, 17, 31, 51th of the storage period), the oil of the samples was extracted by hexane solvent (Scharlau, Spain, chromatography grade) in a manner similar to the previous study (Ghorbani and Hosseini, 2017). Water activity was determined by a w meter instrument (Novasina AG, CH-8853, Switzerland).…”

Advances in cultivar choice, hazelnut orchard management, and nut storage to enhance product quality and safety: an overview

“…1), based on the original quality of the harvested nuts 139 . However, the post‐harvest life of hazelnuts is greatly dependent on the temperature and relative humidity associated with the storage conditions, 140, 141 despite the fact that, to overcome the effects of storage, hazelnuts must be dried. Storage techniques and processing methods are also strategic as procedures are able to block, or at least control, the effects of the lipid degradation and thus the loss of quality, together with the shelf‐life extension of kernels 142 .…”