Kernels in the shell were compared to bare kernels with pellicles, half nuts, blanched nuts, finely chopped nuts, and roasted nuts. Whole nuts and whole kernels were stable for up to two years of storage provided they had not been exposed to high temperatures. Nuts stored at low temperatures (0 and 5°C) did not lose significant amounts of vitamin E. Increasing surface area by dividing nuts or finely chopping them, increased the loss of vitamin E. Samples that had lower surface areas did not lose much vitamin E and peroxide value was low. Higher roasting temperatures caused losses in vitamin E and increased peroxide values at the beginning and during storage, even when stored at 0°C. Intact nuts and low storage temperatures did not show changes in fatty acid composition. High temperature treatments changed fatty acid composition, mainly decreasing linoleic initially and finally oleic acids.
“grassy” or “paint-like” flavors in food ( Frankel, 1983 ). Hydrolysis of triacylgycerides yields free fatty acids. Quantifying the peroxide value, hexanal content, and free fatty acids provides insight into the amount of lipid degradation that has
acidity ( A ) or peroxide value ( B ) measured according to the Official method (EU 1989/2003 modifying the ECC 2568/91) and the Oxitester. Regression equations: ( A ) y = 1.06x + 0.001, R 2 = 0.996; ( B ) y = 1.09x – 0.21, R 2 = 0.995. Phenolic
not find a consistent increase in PV with increasing storage time ( Kiritsakis et al., 1998 ; Yousfi et al., 2008 ), in line with our findings. Fig. 3. Changes in peroxide values [milliequivalents active oxygen (O 2 ) per kilogram oil] of oils
determined on the dried sample by nuclear magnetic resonance (Maran-S60; Oxford Instruments, Abingdon, UK) and referred on the basis of dry fruit weight. Olive oil physicochemical analyses (FFAs, peroxide value, ultraviolet absorption characteristics at 232
peroxide (H 2 O 2 ), which decomposes rapidly into harmless products water and oxygen ( Randhawa et al., 2012 ). Hydrogen peroxide is generated via superoxide, presumably in a noncontrolled manner, during electron transport processes such as photosynthesis
(arugula, radish) and three lettuce cultivars (Othilie, Rouxai, Xandra) after daily foliar spray with one of eight hydrogen peroxide concentrations (0, 25, 50, 75, 100, 125, 150, or 200 mg·L −1 ). Percentages were generated by dividing the pooled values for
( Table 2 ). All applied treatments, except the low rate of hydrogen peroxide + peroxyacetic acid (2.31 mL·L –1 total a.i. applied), significantly reduced the powdery mildew severity ( F = 13.18, P = 0.0008) and disease progress (AUDPC) ( F = 18
values ± se . Different letters indicate significant differences among treatments. Multiple comparisons of means were performed using Tukey’s test at the 0.05 significance level. FW = fresh weight. MDA and proline content. Lipid peroxidation of cell
refined oil. Table 5. Olive oil quality from one sample each of three cultivars (Arbequina, Arbosana, and Koroneiki) harvested in 2013 and analyzed for free fatty acids (FFA), peroxide value (PV), K value of ultraviolet absorption at 232 nm [K232