Agro Processing and Technology Division, CSIR - National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram, India.
Research Planning and Business Development, CSIR - National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram, India.
Crit Rev Food Sci Nutr. 2023;63(31):10849-10865. doi: 10.1080/10408398.2022.2082371. Epub 2022 Jun 2.
Antioxidants are compounds that are essential for the human body which prevents cell from disease causing free radicals. Antioxidants are present in a wide range of fruits, vegetables, and spices. However, a considerable amount of antioxidants is lost during the post-harvest drying operation of agro produces for their shelf-life enhancement. Hence, retention of antioxidants becomes utmost importance in preserving the nutritional aspects of fruits and vegetables. Compared to conventional hot air drying, methods like freeze drying, vacuum drying, and dehumidified drying helps in the retention of antioxidants. However, the drawbacks prevalent in current drying practices, such as high-power consumption and high capital cost, could be eliminated by adopting novel drying mechanisms. This review focuses on various pretreatment methods like ultra-sonication, high pressure processing, pulsed electric field and ethanol treatment prior to drying operation helps in enhancing the drying efficiency with maximum retention of antioxidants. In addition, hybrid drying technologies such as microwave assisted drying, IR-radiated drying and electro-magnetic assisted drying methods also could significantly improve the retention of antioxidants.HIGHLIGHTSDrying is the most commonly adopted unit operation for enhancing the shelf life of perishable agro produces.However, drying is accompanied by loss of bioactive, color, texture, and sensory attributes.Compared to conventional drying techniques like hot air drying, methods like freeze drying, vacuum drying and dehumidified drying helps in the retention of antioxidants present in agro/food produces.Pretreatment methods like Ozonation, ultra-sonication, and UV radiation prior to drying are also found to improve the drying performance with good retention of antioxidants.Recent developments like microwave-assisted and IR-assisted drying methods perform well in the retention of antioxidants with less energy consumption.
抗氧化剂是人体必需的化合物，可防止细胞受到致病自由基的伤害。抗氧化剂存在于各种水果、蔬菜和香料中。然而，在农产品的收获后干燥操作中，为了延长其保质期，相当数量的抗氧化剂会流失。因此，在保持水果和蔬菜的营养方面，保留抗氧化剂变得至关重要。与传统的热风干燥相比，冷冻干燥、真空干燥和除湿干燥等方法有助于保留抗氧化剂。然而，当前干燥实践中普遍存在的高功耗和高资本成本等缺点，可以通过采用新型干燥机制来消除。本综述重点介绍了各种预处理方法，如超声处理、高压处理、脉冲电场和乙醇处理，这些方法在干燥操作前有助于提高干燥效率并最大限度地保留抗氧化剂。此外，微波辅助干燥、IR 辐射干燥和电磁辅助干燥等混合干燥技术也可以显著提高抗氧化剂的保留率。
亮点：
干燥是提高易腐农产品保质期最常用的单元操作。
然而，干燥伴随着生物活性、颜色、质地和感官特性的损失。
与热风干燥等传统干燥技术相比，冷冻干燥、真空干燥和除湿干燥等方法有助于保留农产品/食品中的抗氧化剂。
在干燥前进行臭氧处理、超声处理和 UV 辐射等预处理方法也被发现可以改善干燥性能并保持良好的抗氧化剂保留率。
微波辅助和 IR 辅助干燥等最新发展在保留抗氧化剂方面表现良好，且能耗较低。
