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Effect of refining and antioxidants on the storage stability of edible vegetable oils

KrishiKosh

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Title Effect of refining and antioxidants on the storage stability of edible vegetable oils
 
Creator Anjani
 
Contributor Rajvir Singh
 
Subject null
 
Description The present study was undertaken to evaluate the effect of refining and addition of antioxidants on the
storage stability of some edible vegetable oils viz. cotton, flaxseed, groundnut, soybean and mustard. The seeds
were collected from farmer’s field at Hisar, Haryana and grounded to powder. Oil was extracted by Soxhlet
method using petroleum ether (60-80°C) for 8 h. Solvent extraction processes include basically three steps:
preparation, extraction, and desolventizing. Refining of oils was done by chemical method in different steps:
degumming, neutralization, bleaching and deodorizing. The dried defatted seed meal of sunflower and sesame
were extracted with acetone by Soxhlet method for 8 h. The calculated quantity 200 ppm of Tertiary Butylated
Hydroxy Quinone and Propyl Gallate and 500, 1000 and 2000 ppm of acetone extracts of defatted seed meals of
sesame and sunflower, each were with the crude and refined oil taken in an open mouthed beaker and wrapped
with aluminium foil. The mixture was thoroughly homogenised and the samples were prepared in duplicate. Then
control sample was also prepared and the oil samples were stored at 50°C thermostat. Required quantity of the
samples were removed periodically and studied for oxidative quality indices viz. free fatty acid, peroxide value, panisidine
value, total oxidation value, conjugated dienes, carotenoid, total tocopherol, thiobarbituric acid value and
fatty acid composition. Free fatty acid ranged from 0.9 to 3.49 (% as oleic acid) for crude oils and from 0.3 to 1.98
(% as oleic acid) for refined oils. Peroxide value ranged from 1.26 to 3.4 (meq/kg) for crude oils and for refined oil
range was 0.92 to 1.5 (meq/kg). p-Anisidine value ranged from 1.75 to 10.14 and 1.03 to 4.77 for crude and
refined oils respectively. Total oxidation values ranged from 6.41 to 16.94 and 3.36 to 6.74 respectively for crude
and refined oils. Conjugated dienes ranged from 0.36 to 3 (% as dienoic acid) for crude oils and 0.21 to 3.2 (% as
dienoic acid) for refined oils. The range of carotenoid was 41.3 to 126.09 (mg/kg) for crude oils and 30.2 to 75.69
(mg/kg) for refined oils. Total tocopherol value ranged from 476 to 1620 (mg/kg) and 219 to 829 (mg/kg) for
crude and refined oil respectively. Thiobarbituric acid ranged from 4.63 to 15 (meq/kg) for crude oils and for
refined oils it was 2.73 to 9.3 (meq/kg).
Stability order of oils under study was Groundnut > Mustard > Flaxseed > Cotton > Soybean. Sesame
and sunflower meal acetone extracts at varying concentration, when added to vegetable oils lower the free fatty
acid value, peroxide value, p-anisidine value, total oxidation value, conjugated dienes and thiobarbituric acid value
compared to control under similar conditions. Thus, acetone extracts of sesame and sunflower meals have high
antioxidant efficacy against vegetable oil protection even high than propyl gallate. Among the both meal extracts
sesame meal extract is more effective than sunflower meal extracts. Present study could be an effective
introduction to the antioxidant potential of seed meals that are being discarded as by-products. Refined vegetables
oil was more prone to oxidative deterioration than crude oil because natural antioxidants such as total tocopherol,
sterol and carotenoid had been lost during refining.
 
Date 2018-10-18T09:18:23Z
2018-10-18T09:18:23Z
2018
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/5810081729
 
Language en
 
Format application/pdf
 
Publisher CCSHAU