Abstract:The effects of packaging bags with different colors on the fatty acid oxidation in walnut kernel were explored in this paper. At the following experimental conditions (temperature: 35±1 ℃, relative humidity: 85~95%, and fluorescent light intensity: 1000 Lux), the effects of blue (transmittance of 65% to a light with the wavelength of 500~520 nm), green (transmittance of <48% to a light with the wavelength of 400~750 nm), and red (transmittance of >70% to a light with the wavelength of >630 nm) polyethylene (PE) packaging bags on the sensory quality, activities of antioxidant enzymes and lipoxygenase (LOX), and lipid oxidation related indexes of walnut kernels were studied. The results revealed that compared with the transparent packaging bag (CK), blue and green packaging bags could effectively maintain the sensory qualities of walnut kernel, significantly slow down the increase in the LOX activity, oil acid/peroxide values, and the amounts of saturated fatty acids, while inhibit the decrease in the oil iodine value, the amounts of unsaturated fatty acids, and index of unsaturated fatty acid (IUFA). The blue packaging bag showed a better effect on maintaining the activities of antioxidant enzymes in the walnut kernels than its green counterpart. However, the activities of antioxidant enzymes and IUFA values after 20 and 40 days of storage in the red packaging bag were lower than those of CK. Therefore, the blue packaging bag with short wavelength light transmission and the green packaging bag with low light transmittance were beneficial in alleviating the oxidation of fatty acid in walnut kernels, while the red packaging bag with high transmittance on long-wavelength light was unsuitable for the storage of walnut kernel.
