RESUMEN
Mustard oil blends were investigated for fatty acid composition and oxidative stability during storage for 3 months at room temperature (15 °C to 35 °C). The blends were prepared using raw mustard oil with selected refined vegetable oils namely; palm, safflower, soybean, rice bran, sunflower and sesame oil (raw). The fatty acid compositions of all these blends were studied using GLC. The developed blends were found to obey the ideal fatty acid ratio as laid down by health agencies i.e. 1:2:1:: SFA:MUFA:PUFA. The oxidative stability of blends was studied by measuring peroxide value (PV), Kries and Thiobarbituric acid (TBA) test. Blends MPSu (mustard oil, palm oil and sunflower oil), MPT (mustard oil, palm oil and sesame oil) and MPGr (mustard oil, palm oil and groundnut oil) were more stable than other blends during storage. The presence of mustard oil in all blends might make them a healthier option for many consumers as it is a rich source of ω-3 fatty acids and has anti-carcinogenic properties.
RESUMEN
Changes in chemical composition and the activities of hydrolytic enzymes during four different stages of maturity, viz. mature green (MG), color turning (CT), ripe (R), and overripe (OR), have been studied in guava fruits cv. Banarsi Surkha. Chlorophyll content decreased while carotenoid content increased during ripening. Starch content decreased with concomitant increase in alcohol-soluble sugars. Cellulose, hemicellulose, and lignin also decreased up to ripe stage, while pectin continued to decrease up to OR stage. PG (polygalacturonase) and cellulase exhibited progressive increase in activity throughout ripening, whereas pectin methyl esterase (PME) activity increased up to CT stage and decreased at R stage. The activities of alpha-amylase and beta-amylase decreased significantly with ripening. The most notable metabolic changes occurred between MG and CT stage, implying that for improved postharvest handling, guava fruits may be harvested at CT stage.