Hydrolytic Stability and Changes in E Vitamers and Oryzanol of Extruded Rice Bran During Storage

Shin, Tai-Sun; Godber, John; Martin, Daniel E.; Wells, John Henry

doi:10.1111/j.1365-2621.1997.tb15440.x

Cited by 135 publications

(89 citation statements)

References 34 publications

(36 reference statements)

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“…The highest amount of oil was extracted at 110°C, which resulted in the lowest value for the γ-oryzanol concentration for material pretreated at that temperature. The amount of γ-oryzanol remained quite stable as the heating temperature was increased from 60°C to 110°C, as confirmed elsewhere 20,[25][26][27] . However, heating at a temperature more than 120°C enhanced degradation of γ-oryzanol, as reported elsewhere 20,27 .…”

Section: Effect Of Pretreatment Processes On Amount Of γ-Oryzanolsupporting

confidence: 64%

“…The optimum temperature for lipase activity is around 60-70°C, so that the increased amount of low molecular weight compounds might be γ-oryzanol 26,29 . However, at the higher temperature of 100°C, the loss of moisture inside the material resulted in no activity of enzyme, so the γ-oryzanol level was low 25,27 . Moreover, a pretreatment temperature higher than 110°C promotes degradation of γ-oryzanol, which resulted in the lowest value, as shown for the 180°C pretreatment in Fig.…”

Section: Effect Of Pretreatment Processes On Amount Of γ-Oryzanolmentioning

confidence: 99%

“…The rice bran, when heated to 110°C, turned from a pale yellow to a dark brown, with a rancid smell and bad oil quality (oxidative rancidity) because heat burned the bran. Residual lipase activity in the rice bran after heating at 110°C released large quantities of free fatty acids and γ-oryzanol and added to the rancid smell 25 . Hot air heating, which heated the material to the desired temperature by convection, decreased the amount of extracted rice bran oil, as shown in Fig.…”

Section: Effect Of Pretreatment Processes On Amount Of Rice Bran Oilmentioning

confidence: 99%

“…The statistical analysis shown in Table 2 confirmed that all experiments showed significant differences. Heating promotes fatty acid degradation by cleavage of oils to free fatty acids and low molecular weight compounds such as γ-oryzanol 25,28 . Even though microwaves are considered the most energy-efficient type of heating and a rapid method for bran stabilization, microwave pretreatment still has limitations that require preliminary tests of feasibility for any application 26 .…”

Section: Effect Of Pretreatment Processes On Amount Of γ-Oryzanolmentioning

confidence: 99%

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Pretreatment to increase yield and antioxidant activity of γ-oryzanol in rice bran oil

Ruen-ngam¹,

Thawai²,

Sukonthamut³

2016

ScienceAsia

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ABSTRACT:Six pretreatment processes to extract oil from Khao Dok Mali 105 rice bran were tested to assess the effect of the processes on the γ-oryzanol content and DPPH scavenging activity of the extract. The pretreatment processes consisted of the following: microwave heating (60-110°C), hot air heating (70-180°C), roasting (60-80°C), parboiling (70°C), autoclaving (121°C), and enzyme (amylase) treatment (50°C). The highest amount of oil was obtained by hot air heating (70°C) of 0.27 g/g of dried rice bran, whereas the highest γ-oryzanol yield was obtained by parboiling 9.8 mg/g of dried rice bran. The highest γ-oryzanol concentration obtained with a roasting pretreatment (60°C) was 46.9 mg/ml of rice bran oil.

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Section: Effect Of Pretreatment Processes On Amount Of γ-Oryzanolsupporting

confidence: 64%

Section: Effect Of Pretreatment Processes On Amount Of γ-Oryzanolmentioning

confidence: 99%

Section: Effect Of Pretreatment Processes On Amount Of Rice Bran Oilmentioning

confidence: 99%

Section: Effect Of Pretreatment Processes On Amount Of γ-Oryzanolmentioning

confidence: 99%

See 2 more Smart Citations

Pretreatment to increase yield and antioxidant activity of γ-oryzanol in rice bran oil

Ruen-ngam¹,

Thawai²,

Sukonthamut³

2016

ScienceAsia

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“…The higher moisture content in the potato chips sharply brought changes much earlier in the oryzanol content of rice bran oil, which may be due to the hydrolytic degradation of rice bran oil when exposed to higher temperature. Shin et al (1997) also found that increased moisture content and extrusion temperature reduces the oryzanol content. Oryzanol (Gamma) acts as an antioxidant in the oil but is lost during the thermal oxidation.…”

Section: Resultsmentioning

confidence: 95%

Effect of frying conditions on the physico-chemical properties of rice bran oil and its blended oil

Mishra

Sharma

2011

J Food Sci Technol

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The changes occurring in rice bran oil and its blend with sunflower oil during repeated frying cycles of dried and moist potato chips were monitored. The parameters assessed were: Colour, Refractive Index, SpecificGravity, Oryzanol Value, Free fatty acid, Iodine Value, Peroxide value, anisidine value, Saponification Value, trans fats and fatty acid composition. No significant changes (p≤0.05) were observed in the refractive index and specific gravity of rice bran oil, sunflower oil and their model blend. The colour of blended oil was lesser than RBO and the intensity of color increased after each frying cycle during the deep fat frying of moistened and dried potato chips. The oryzanol content and iodine value decreased with the frying cycles. The decrease in oryzanol value during the frying operation was more prominent in rice bran oil as compared to the blended oils. The increase in p-anisidine value was more in rice bran oil as compared to blended oil. No significant changes (P<0.05) in the myristic, palmitic and stearic acid composition was observed during the repeated deep fat frying cycles in both the rice bran oil and blended oils samples. The amount of unsaturated fatty acid decreased gradually during repeated deep fat frying cycles in both the oils. The trans fat increased with repeated deep fat frying cycles in both the rice bran and blended oils, when used to fry moistened and dried potato chips. Both the oil samples showed greater formation of trans fatty acids when the moistened potato chips were used during frying.

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Vitamin E

Bramley

Elmadfa

Kafatos

et al. 2000

J. Sci. Food Agric.

480

219

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There is a growing body of evidence to suggest that the dietary intakes of vitamin E are insufficient to protect against the long‐term health risks associated with oxidative stress. Traditional plant breeding and food processing technologies have not concerned themselves with maximising the levels of the tocopherols in the diet, and supplementation is necessary both for nutritive reasons and for the protection of fat‐rich foods against oxidative rancidity. The paper reviews the potential for improving the tocopherol levels in the diet, particularly α‐tocopherol. Genetic technologies have already demonstrated the potential to enhance tocopherol levels by up‐regulation of the final steps in the biosynthetic pathway. Other strategies for the enhancement of the vitamin E content of plant foods are considered both from the perspective of improved bioavailability and the levels in processed foods. Finally some priorities for future research in the field are described. © 2000 Society of Chemical Industry

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Hydrolytic Stability and Changes in E Vitamers and Oryzanol of Extruded Rice Bran During Storage

Cited by 135 publications

References 34 publications

Pretreatment to increase yield and antioxidant activity of γ-oryzanol in rice bran oil

Pretreatment to increase yield and antioxidant activity of γ-oryzanol in rice bran oil

Effect of frying conditions on the physico-chemical properties of rice bran oil and its blended oil

Vitamin E

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