Pretreatment-driven shrinkage regulation in Chinese yam during multiphase microwave drying

IF 5.8 2区农林科学 Q1 ENGINEERING, CHEMICAL

Journal of Food Engineering Pub Date : 2025-09-04 DOI:10.1016/j.jfoodeng.2025.112799

Rongtian An , Linlin Li , Lijuan Wang , Wenchao Liu , Weiwei Cao , Junliang Chen , Guangyue Ren , Min Zhang , Chung Lim Law , Xu Duan

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引用次数: 0

Abstract

Multiphase microwave drying (MMD) is an innovative drying technology that significantly reduces drying time compared to freeze drying (FD) while maintaining similar product quality. However, shrinkage during the evaporation stage remained a major limitation hindering MMD from replacing FD. In this study the effects of three pretreatment methods—ultrasound (US), freeze-thaw cycles (FT), and film coating (FC)—on the shrinkage characteristics of Chinese yam during MMD were investigated.

To elucidate the mechanisms governing shrinkage behavior, we integrated low-field nuclear magnetic resonance (LF-NMR) analysis, which enables rapid detection of the effects of pretreatments on water status, with 2D/3D microstructural characterization using scanning electron microscopy and X-ray micro-computed tomography. Product quality was evaluated based on rehydration capacity and textural properties. The results showed that US pretreatment significantly reduced shrinkage (P < 0.05), with the 400 W treatment achieving the lowest ratio (3.2 %), representing a substantial improvement over the control. This reduction was attributed to the US-induced transformation of bound and immobile water into free water, and the formation of large, uniformly distributed micro-channels. This expanded pore area and optimized pore density distribution, thereby effectively suppressing shrinkage. Additionally, US-400 significantly enhanced rehydration capacity and improved textural properties (P < 0.05), resulting in superior product quality. One freeze-thaw cycle (FT-1) reduced shrinkage by 6 % compared to the control group, but additional FT led to severe shrinkage and quality deterioration. The cassava starch coating with 2 % glycerol (FC-2) reduced shrinkage by 15.8 % compared to the control, but increased drying time, hardness, and crispness, ultimately lowering product quality. In conclusion, US pretreatment at 400 W effectively minimized shrinkage during MMD, offering theoretical and technical support for producing high-quality dried Chinese yam.

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山药多相微波干燥过程中预处理驱动的收缩调控

多相微波干燥（MMD）是一种创新的干燥技术，与冷冻干燥（FD）相比，它显著缩短了干燥时间，同时保持了相似的产品质量。然而，蒸发阶段的收缩仍然是阻碍MMD取代FD的主要限制因素。本文研究了超声波（US）、冻融循环（FT）和涂膜（FC）三种预处理方法对山药MMD收缩特性的影响。为了阐明控制收缩行为的机制，我们将低场核磁共振（LF-NMR）分析与使用扫描电子显微镜和x射线微计算机断层扫描的二维/三维微观结构表征结合起来，该分析能够快速检测预处理对水状态的影响。根据复水能力和结构性能对产品质量进行评价。结果表明，美国预处理显著降低了收缩率（P < 0.05），其中400 W处理的收缩率最低（3.2%），比对照组有了实质性的改善。这种减少归因于us诱导的束缚水和不动水转化为自由水，以及形成均匀分布的大微通道。这扩大了孔隙面积，优化了孔隙密度分布，从而有效地抑制了收缩。此外，US-400显著提高了再水化能力，改善了结构性能（P < 0.05），从而使产品质量更优。与对照组相比，一个冻融循环（FT-1）减少了6%的收缩率，但额外的FT会导致严重的收缩率和质量恶化。与对照组相比，2%甘油（FC-2）的木薯淀粉包衣减少了15.8%的收缩率，但增加了干燥时间、硬度和脆度，最终降低了产品质量。综上所述，400 W的US预处理有效地降低了MMD过程中的收缩率，为生产优质山药干提供了理论和技术支持。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Food Engineering 工程技术-工程：化工

CiteScore

11.80

自引率

5.50%

发文量

275

审稿时长

24 days

期刊介绍： The journal publishes original research and review papers on any subject at the interface between food and engineering, particularly those of relevance to industry, including: Engineering properties of foods, food physics and physical chemistry; processing, measurement, control, packaging, storage and distribution; engineering aspects of the design and production of novel foods and of food service and catering; design and operation of food processes, plant and equipment; economics of food engineering, including the economics of alternative processes. Accounts of food engineering achievements are of particular value.