Abstract: The preservation of fresh walnut kernels during low temperature shelf was studied using fresh walnut kernels of ‘Xiangling’ as raw material. Four modified atmosphere packaging (MAP) treatments and four dosages of short-wave ultraviolet radiation C (UVC) were adopted to treat the fresh shelled kernels with food wrapping film (CK1), vacuum packaging (CK2), and scatter light treatment (CK) was used as control. According to results of the changes of O2 and CO2 concentration in each treatment, texture parameters, sensory quality and microorganism number of kernels from each treatment, 0.03 mm polyethylene 30(PE30) and 1 kJ/m2 UVC was selected as the best parameters respectively for packaging and sterilization. Then, walnuts were treated with MAP and UVC, separately, and in combination under each best parameter, stored at (5±0.5) ℃ to observe the changes of related physiology, quality and microorganisms during shelf life at a low temperature. The results showed that there were no significant differences on the tribute between these treatments with control on 21th day, and no mold was detected. Moreover, on 56th day, the compound treatment acted priorly to each separate one, which significantly reduced both the content of malondialdehyde (MDA) and acid value (P<0.05) than control. However, the content of total phenol, oil and protein was not affected by the treatment, and the soluble sugar was decreased (P<0.05). Furthermore, the visible mold appeared till on the 70th day, which 10 days later than control. The compound treatments also inhibited the activities of phospholipase D (PLD) and lipoxygenase (LOX) stronger than the other two treatments, providing the physiological basis of combined MAP and UVC maintained the quality of fresh kernels through the inhibition of membrane degradation.
[1] 马艳萍, 马惠玲, 刘兴华, 等.鲜食核桃和干核桃贮藏生理及营养品质变化比较[J].食品与发酵工业, 2011, 37(3):235-238. MA Y P, MA H L, LIU X H, et al.Comparison of physiology and nutrition in dry and fresh walnut during the storage[J].Food and Fermentation Industries, 2011, 37(3):235-238. [2] 韩强, 郜海燕, 陈杭君, 等.ClO2处理和包装方法对鲜核桃仁贮藏品质的影响[J].中国食品学报, 2017,17(5):130-137. HAN Q, GAO H Y, CHEN H J, et al.Effects of ClO2 treatment and packing methods on storage quality of fresh walnut kernel[J].Journal of Chinese Institute of Food Science and Technology, 2017,17(5):130-137. [3] 贾晓辉, 王文辉, 佟伟, 等.自发气调包装对库尔勒香梨采后生理及贮藏品质的影响[J].中国农业科学, 2016, 49(24):4 785-4 796. JIA X H, WANG W H, TONG W, et al.Effect of modified atmosphere packaging on postharvest physiology and quality of ‘Korla Xiangli’ pears during storage[J].Scientia Agricultura Sinica, 2016, 49(24):4 785-4 796. [4] 郭园园, 鲁晓翔, 李江阔, 等.青皮鲜核桃低温贮藏后货架期品质的变化[J].食品与发酵工业, 2014, 40(2):213-218. GUO Y Y, LU X X, LI J K, et al.Quality changes of green Juglans during shelf life after cold storage[J].Food and Fermentation Industries, 2014, 40(2):213-218. [5] 斯跃洲, 高佳, 李焕秀, 等.包装膜透性对西兰花采后冷藏品质变化的影响[J].现代食品科技, 2017, 33(7):186-191;150. SI Y Z, GAO J, LI H X, et al.Effect of packaging film permeability on the quality of postharvest broccoli during cold storage[J].Modern Food Science and Technology, 2017, 33(7):186-191;150. [6] 初丽君, 王琼, 王敏, 等.不同厚度PE膜包装对鲜食石榴籽粒保鲜效果的影响[J].保鲜与加工, 2017, 17(6):20-26. CHU L J, WANG Q, WANG M, et al.Effect of PE film thickness on preservative effect of ready-to-eat pomegranate seeds[J].Storage and Process, 2017, 17(6):20-26. [7] FAN X T, HUANG R Z, CHEN H Q.Application of ultraviolet C technology for surface decontamination of fresh produce[J].Trends in Food Science & Technology, 2017, 70:9-19. [8] MANZOCCO L, PLAZZOTTA S, MAIFRENI M, et al.Impact of UV-C light on storage quality of fresh-cut pineapple in two different packages[J].LWT-Food Science and Technology, 2016, 65:1 138-1 143. [9] MUKHOPADHYAY S, UKUKU D O, JUNEJA V, et al.Effects of UV-C treatment on inactivation of Salmonella enterica and Escherichia coli O157∶H7 on grape tomato surface and stem scars, microbial loads, and quality[J].Food Control, 2014, 44:110-117. [10] MANZOCCO L, DA PIEVE S, MAIFRENI M.Impact of UV-C light on safety and quality of fresh-cut melon[J].Innovative Food Science & Emerging Technologies, 2011, 12(1):13-17. [11] 国家卫生和计划生育委员会, 国家食品药品监督管理总局.GB 4789.2—2016 食品安全国家标准 食品微生物学检验菌落总数测定[S].北京:中国标准出版社, 2016. State Health and Family Planning Commission of the People′s Republic of China, State Food and Drug Administration.GB 4789.2—2016 National food safety standards Determination of total bacterial count in food microbiological examination[S].Beijing:China Standards Press, 2016. [12] SABAGHI M, MAGHSOUDLOU Y, KHOMEIRI M, et al.Active edible coating from chitosan incorporating green tea extract as an antioxidant and antifungal on fresh walnut kernel[J].Postharvest Biology and Technology, 2015, 110:224-228. [13] 曹建康, 姜微波, 赵玉梅.果蔬采后生理生化实验指导[M].北京:中国轻工业出版社, 2007. CAO J K, JIANG W B, ZHAO Y M.Experimental Guidance of Postharvest Physiology and Biochemistry of Fruits and Vegetables[M].Beijing:China Light Industry Press, 2007. [14] 徐宏化, 程慧, 王正加, 等.美国山核桃总多酚与总黄酮含量及抗氧化活性[J].核农学报, 2016, 30(1):72-78. XU H H, CHENG H, WANG Z J, et al.The study of total polyphenols, total flavonoids and antioxidant capacity in pecan [Carya illinoinensis (wangenh.) K.Koch] kernerls[J].Journal of Nuclear Agricultural Sciences, 2016, 30(1):72-78. [15] 中华人民共和国国家卫生和计划生育委员会. GB 5009.227—2016 食品安全国家标准 食品中酸价的测定[S].北京:中国标准出版社, 2016. State Health and Family Planning Commission of the People′s Republic of China.GB 5009.227—2016 National food safety standards Determination of acid value in food[S].Beijing:China Standards Press, 2016. [16] 中华人民共和国国家卫生和计划生育委员会. GB 5009.229—2016 食品安全国家标准 食品中过氧化值的测定[S].北京:中国标准出版社, 2016. State Health and Family Planning Commission of the People′s Republic of China.GB 5009.229—2016 National food safety standards Determination of peroxide value in food[S].Beijing:China Standards Press, 2016. [17] 宁正祥. 食品成分分析手册[M].北京:中国轻工业出版社, 1998. NING Z X.Food Composition Analysis Manual[M].Beijing:China Light Industry Press, 1997:10-65. [18] LIN Y F, LIN H T, LIN Y X, et al.The roles of metabolism of membrane lipids and phenolics in hydrogen peroxide-induced pericarp browning of harvested longan fruit[J].Postharvest Biology and Technology, 2016, 111:53-61. [19] 纪宗亚. 质构仪及其在食品品质检测方面的应用[J].食品工程, 2011(3):22-25. JI Z Y.Application of texture analyzer in the assessment for food quality[J].Food Engineering, 2011(3):22-25. [20] 田竹希, 龙明秀, 李咏富, 等.短波紫外线照射和60Co-γ辐照处理对大樱桃贮藏品质的影响[J].食品科学, 2019,40(23):269-276. TIAN Z X, LONG M X, LI Y F, et al.Effects of short-wave ultraviolet (UV-C) light and 60Co-γ irradiation on the storage quality of cherry fruits[J].Food Science, 2019,40(23):269-276. [21] CHEN C, HU W Z, HE Y B, et al.Effect of citric acid combined with UV-C on the quality of fresh-cut apples[J].Postharvest Biology and Technology, 2016, 111:126-131. [22] 王小玲, 于一尊, 高柱, 等.羽扇豆套种对猕猴桃叶片和果实丙二醛含量的影响[J].北方园艺, 2018(24):54-58. WANG X L, YU Y Z, GAO Z, et al.Effects of intercropping lupin on malondialdehyde content in kiwifruit leaf and fruit[J].Northern Horticulture, 2018(24):54-58. [23] 葛双双, 张雯雯, 李坤, 等.余甘子核仁油的体外抗氧化活性及其作用机理[J].食品科学, 2017,38(15):127-134. GE S S, ZHANG W W, LI K, et al.Antioxidant activity and mechanism in vitro of Phyllanthus emblica L.seed oil[J].Food Science, 2017,38(15):127-134. [24] 古明亮, 徐茂芹, 刘侣丹, 等.不同贮藏温度对核桃品质的影响[J].四川农业与农机, 2018, (5):28-30. GU M L, XU M Q, LIU L D, et al.Effect of different storage temperature on walnut quality[J].Sichuan Agriculture and Agricultural Machinery, 2018, (5):28-30. [25] 中华人民共和国国家卫生健康委员会, 国家市场监督管理总局.GB 2716—2018 食品安全国家标准 植物油[S].北京:中国标准出版社, 2018. State Health and Family Planning Commission of the People′s Republic of China, State Food and Drug Administration.GB 2716—2018 National food safety standards vegetable oil[S].Beijing:China Standards Press, 2018. [26] 郑丽静, 聂继云, 闫震.糖酸组分及其对水果风味的影响研究进展[J].果树学报, 2015, 32(2):304-312. ZHENG L J, NIE J Y, YAN Z.Advances in research on sugars, organic acids and their effects on taste of fruits[J].Journal of Fruit Science, 2015, 32(2):304-312. [27] 邓丽莉, 潘晓倩, 生吉萍, 等.考马斯亮蓝法测定苹果组织微量可溶性蛋白含量的条件优化[J].食品科学, 2012, 33(24):185-189. DENG L L, PAN X Q, SHENG J P, et al.Optimization of experimental conditions for the determination of water soluble protein in apple pulp using coomassie brilliant blue method[J].Food Science, 2012, 33(24):185-189. [28] LI J W, WANG X M.Phospholipase D and phosphatidic acid in plant immunity[J].Plant Science, 2019, 279:45-50. [29] POURNIK S, ABBASI-ROSTAMI M, SADEGHIPOUR H R, et al.True lipases beside phospholipases contribute to walnut kernel viability loss during controlled deterioration and natural aging[J].Environmental and Experimental Botany, 2019, 164:71-83. [30] 鞠延仑, 房玉林, 张莉, 等.赤霞珠葡萄脂氧合酶活性测定及脂肪酸组分的变化[J].食品科学, 2015, 36(5):115-119. JU Y L, FANG Y L, ZHANG L, et al.Determination of lipoxygenase activity and change in fatty acid composition in Cabernet Sauvignon grape berries[J].Food Science, 2015, 36(5):115-119.
2021, Vol. 47 
