The Antioxidant Activity And Stability Of ?-carotene On Perilla Oil

Perilla oil has a high content of unsaturated fatty acids,which is the most abundant plant resource of?-linolenic acid and has a high nutritional value.?-Carotene is an important source of human vitamin A,with strong antioxidant capacity,natural coloring and high safety advantages,is a good food additives and nutritional supplements.The fatty acid composition of Perilla oil was determined by GC-MS,and using?-carotene as an additive,the effects of different dosages on the color,antioxidant activity and storage stability of Perilla oil were also studied in this paper.And the stability of Perilla oil with?-carotene was investigated.Meanwhile,a method for quantitative analysis of pigment content during oil storage was established by digital image colorimetry.The main results are as follows:1)Effects of?-carotene on color and antioxidant activity of perilla oil.Perilla oil was rich in unsaturated fatty acids,especially?-linolenic acid(C18:3n-3,65.83%),linoleic acid(C18:2n-6,13.50%)and oleic acid(C18:1n-9,11.32%).Meanwhile,?-carotene had significant effects on the brightness(L^*),chroma(C^*)and hue angle(h^*)of perilla oil(P<0.05).The initial color of perilla oil was slight yellowish-green,and the color gradually deepened with the increase of?-carotene and became orange-red.Moreover,as the amount of pigment added increases,the antioxidant capacity of the oil gradually increases,being maximum when the amount added was 0.02%.Compared with the control group,the scavenging ability for DPPH radical,ABTS radical and Fe³⁺ reduction antioxidant capacity were 22.55,17.83 and 11.82 mmol TEAC/100g.The semi-inhibitory concentrations of hydroxyl radicals and superoxide anion radicals were 0.529,0.711 mg/mL,respectively.2)Effect of?-carotene on the storage stability of perilla oil.During the 0?12 days of storage of perilla oil,the color gradually becomes lighter and transitioning from orange-red to pale yellow-green.The TBARS value increased from 0.58?g/mL to 2.80?g/mL,and the viscosity increased from 0.66 Pa.s to 0.88 Pa.s,the free radical scavenging ability was gradually reduced.The addition of?-carotene can delay the oxidative degradation rate of oils.As the amount of pigment added increases,the TBARS value and viscosity increase rate slowed down.When the amount of pigment added was 0.02%of oil quality,the free radical scavenging ability was significantly higher than the control group.3)Study on the stability of?-carotene in perilla oil.Temperature,light,metal ions and antioxidants have significant effects on beta-carotene.The pigment was stable at 4?in the dark,and the retention rate was 58.53%after storage for 10 h at 90?,and the retention rate decreased to47.30%after 90 min of UV irradiation.Mg²⁺,Zn²⁺,Fe³⁺and Al³⁺were not conducive to the stability of?-carotene,especially Fe³⁺has a strong destructive effect,and the pigment remains only 19.57%after storage for 10 h.BHA,BHT and TBHQ have a protective effect on?-carotene,while ascorbic acid has a slight degradation.4)Quantitative analysis of?-carotene during storage of perilla oil by image colorimetry.The quantitative relationship between green effective intensity(IG)and?-carotene content in the RGB color space was established:y=23.397x-0.00002,R²=0.9948.The content of?-carotene in the process of storage of perilla oil was determined by UV spectrophotometry and digital image colorimetry.It was found that the digital image colorimetric was relatively insufficient in sensitivity and detection limit.But the method was simple,intuitive and cost-effective,and could realize non-destructive testing.It was considered that?-carotene could effectively improve the color,antioxidant capacity and oxidation stability of Perilla oil.Then,perilla oil supplemented with?-carotene should be protected in a low temperature and dark environment,avoiding contact with metal ions,or added antioxidants to maintain its nutritional quality.In addition,image colorimetry can be used as an effective alternative method for the quantitative analysis of carotenoids in oils by ultraviolet spectrophotometry.