TitleComparison of analytical techniques to evaluate the effect of drying on oxidative status of sliced almonds during storage
NameGandhi, Shreya D. (author), Hartman, Dr. Thomas G (chair), Yam, Dr Kit L (internal member), Ho, Dr. Chi-Tang (internal member), Rutgers University, Graduate School - New Brunswick,
Lipids in nutrition,
DescriptionAlmonds (Prunus amygdalus) are highest produced tree nuts worldwide, grown mainly in Mediterranean climate. Almond contains approximately 49% total lipids of which 12g is polyunsaturated fat, 30.9% monounsaturated fat and 3.7% saturated fat. About 90% of its total fatty acid composition is unsaturated, where oleic acid is 60-70% and linoleic acid 14-26%. The unsaturated fatty acids makes the almonds susceptible to oxidative degradation by producing volatile compounds, off flavor and odor decreasing their nutritional value. The deterioration rate of the almonds lipid fraction during storage due to the oxidative process is of a great economic and nutritional importance. Therefore, before storage the fruit is subjected to multi-processing steps in order to improve its quality in term of storage stability. In this connection, the drying step and storage conditions are of decisive importance. The drying step involves removal of moisture to prevent hydrolysis and enzymatic degradation during storage which cause split of triglyceride into glycerol and free fatty acid. However over drying or under drying could lead to oxidative degradation. The combination of various analytical techniques is recommended to evaluate oxidative status as no single method is available to analyze both primary and secondary oxidation products together. In this connection, this project aims at providing most effective analytical technique that evaluates the efficiency of the drying conditions on the storage stability of sliced almonds. Therefore, four different analytical techniques have been selected, namely: Iodometric titration for peroxide value, titration method for Free Fatty acid (Acid Value), UV spectrophotometry for conjugated diene and triene and GC/MS for semi-volatile and volatile compounds were used. This study shows a positive effect of the used drying conditions on the oxidative stability since the concentration of peroxides and conjugated dienes of dried almonds decreased as compared to those of non dried and ambient dried. A constant curve for free fatty acids was obtained showing that drying was done effectively as no hydrolysis has been observed. The GC-MS method seems to be the most suitable method which gives a real picture of drying effect on the oxidative status of the stored sliced almonds.
NoteIncludes bibliographical references
Noteby Shreya D. Gandhi
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.