Ahad Tehmeena, Gull Amir, Nissar Jasia, Masoodi Lubna, Rather A H
Department of Food Science and Technology, SKUAST-K, Shalimar, Srinagar, 190025 India.
Department of Food Science and Technology, University of Kashmir, Srinagar, 190006 India.
J Food Sci Technol. 2020 Oct;57(10):3556-3563. doi: 10.1007/s13197-020-04387-5. Epub 2020 Apr 8.
The effect of antioxidants, temperature, packaging materials and storage periods was investigated in medium shelled walnut kernels (Hamdan) variety. The kernels were mechanically dried (40 °C), standardized and treated with butylated hydroxylanisole and butylated hydroxytoluene in combination at concentrations (0.015%) each. Then packed in laminates under vacuum and high density polyethylene non vacuum packaging materials and stored under ambient and refrigerated temperature conditions (4 °C) for a period of 9 months. All tested extracts possessed appreciable antioxidant potential. The bioactive compounds were identified by using chromatographic techniques (GC-MS and LC-MS). Before storage dried kernels exhibited high values of total phenols (31.23 mgGAE/gm), DPPH (215.13 µmol TAEg) and low value of non enzymatic browning (0.63 OD). Walnuts packed in laminates under vacuum and refrigerated conditions exhibited higher values of total phenols, total flavonoids, DPPH and subsequently lower change in non-enzymatic browning reactions throughout the experiment. After 90 days of storage maximum loss in total phenols and DPPH value and highest value of non enzymatic browning was observed in high density polyethylene non vacuum packaging materials under ambient temperature. The major phenolic components identified by GC/MS and LC/MS analysis were linoleic acid, oleic acid, hexadecanoic acid, epicatechin, quercetin, epicatechin and ellagic acid respectively. This study validates the antioxidant potential of the walnut kernels and the positive relationship between total phenolic content, total flavonoids and antioxidant activity.
研究了抗氧化剂、温度、包装材料和储存时间对中壳核桃品种（哈姆丹）果仁的影响。果仁经过机械干燥（40°C）、标准化处理，并分别以0.015%的浓度用丁基羟基茴香醚和丁基羟基甲苯联合处理。然后分别采用真空层压包装和高密度聚乙烯非真空包装，并在环境温度和冷藏温度条件（4°C）下储存9个月。所有测试提取物均具有可观的抗氧化潜力。通过色谱技术（气相色谱-质谱联用仪和液相色谱-质谱联用仪）鉴定生物活性化合物。储存前，干燥果仁的总酚含量（31.23mg没食子酸当量/g）、二苯基苦味酰基自由基清除能力（215.13µmol Trolox当量/g）较高，非酶褐变值较低（0.63 OD）。在整个实验过程中，真空层压包装并冷藏的核桃总酚、总黄酮、二苯基苦味酰基自由基清除能力值较高，非酶褐变反应变化较小。储存90天后，在环境温度下，高密度聚乙烯非真空包装材料中的果仁总酚和二苯基苦味酰基自由基清除能力值损失最大，非酶褐变值最高。通过气相色谱/质谱联用仪和液相色谱/质谱联用仪分析鉴定的主要酚类成分分别为亚油酸、油酸、十六烷酸、表儿茶素、槲皮素、表儿茶素和鞣花酸。本研究验证了核桃仁的抗氧化潜力，以及总酚含量、总黄酮与抗氧化活性之间的正相关关系。
