Process analysis is an important step for online food quality control during food processing. Among the emerging non-destructive examination techniques that offer rapid detection, terahertz spectroscopy has attracted attention in analysing food processes based on various quality parameters. Moreover, calibration and chemometric methods are frequently used for spectral data analysis. The system normally consists of processing equipment and terahertz time-domain spectral imaging (THz-TDS), which often exhibits high prediction accuracy combined with appropriate chemometrics methods. Therefore, terahertz spectroscopy has been considered highly suitable for on-site and in-situ process analysis to enhance manufacturing and thus improve product quality. In this review, applications of THz-TDS in food processes of dehydration, storage, freezing, and fermentation, as well as other areas, are introduced and discussed. Among these, terahertz technology has attracted intensive research for process analysis related to moisture changes, such as dehydration and storage under natural drying conditions. Emerging techniques of THz-TDS with other processing techniques, such as hot air drying (HAD) and microwave vacuum dehydration (MVD), are frequently investigated. Applications in other areas, including analysing fermentation, freezing, and hygroscopic processes, were also reported. For freezing analysis, it is mainly used to analyze (i) the effect of repeated freezing and thawing on meat and (ii) the growth rate of ice crystals. In analysing fermentation processing, although most of the research has confirmed the feasibility of THz-TDS, further investigation regarding the accuracy is still awaited. The combination of THz-TDS with calibration and chemometrics has been widely employed in analysing the non-linear changes of quality attributes during food processing with the emergence of numerous related research in recent years. It is highly suitable for analysing moisture content and other polar substances such as hydrogen sulfide and ammonia. Despite such high performance, drawbacks of high cost, interference from high moisture content, and high disturbance of other constituents such as protein are still significant obstacles to the universalization of THz-TDS.

中文翻译：

---

通过太赫兹光​​谱成像对食品加工过程进行新颖分析：近期研究结果综述

过程分析是食品加工过程中在线食品质量控制的重要步骤。在提供快速检测的新兴无损检测技术中，太赫兹光谱在基于各种质量参数分析食品过程方面引起了人们的关注。此外，校准和化学计量方法经常用于光谱数据分析。该系统通常由处理设备和太赫兹时域光谱成像（THz-TDS）组成，通常与适当的化学计量学方法相结合，表现出较高的预测精度。因此，太赫兹光谱被认为非常适合现场和原位过程分析，以增强制造能力，从而提高产品质量。本文介绍并讨论了太赫兹时域光谱技术在食品脱水、储存、冷冻、发酵等过程中的应用。其中，太赫兹技术吸引了对与水分变化相关的过程分析的深入研究，例如自然干燥条件下的脱水和储存。 THz-TDS 新兴技术与其他处理技术（例如热风干燥 (HAD) 和微波真空脱水 (MVD)）经常受到研究。还报道了其在其他领域的应用，包括分析发酵、冷冻和吸湿过程。对于冷冻分析，主要用于分析（i）反复冷冻和解冻对肉类的影响以及（ii）冰晶的生长速度。在分析发酵过程时，虽然大多数研究已经证实了THz-TDS的可行性，但其准确性仍有待进一步研究。 THz-TDS与校准和化学计量学的结合已被广泛应用于分析食品加工过程中质量属性的非线性变化，近年来相关研究不断涌现。它非常适合分析水分含量和其他极性物质，例如硫化氢和氨。尽管具有如此高的性能，但高成本、高水分含量的干扰以及蛋白质等其他成分的高干扰仍然是 THz-TDS 普及的重大障碍。