Bioscience Methods 2024, Vol.15, No.6, 327-336 http://bioscipublisher.com/index.php/bm 329 human diet, particularly in markets where sweet potato consumption is not widespread (Galvao et al., 2021). The study investigates the consumption behavior of sweet potato consumers in Beijing, China, and analyzes how different market segments prioritize sweet potato products based on factors like nutritional value, taste, and convenience. It provides an in-depth look at the growing interest in sweet potatoes as a functional food in urban China (Zhang et al., 2018). 3 Post-Harvest Processing Techniques for Sweet Potatoes Post-harvest processing of sweet potatoes plays a crucial role in maintaining their quality, extending shelf life, and enhancing their economic value. Various techniques, including grading, cleaning, drying, and storage, have been developed to minimize post-harvest losses and ensure the best quality for consumption or further processing (Fang, 2024a). 3.1 Grading, cleaning, and peeling of sweet potatoes Grading and cleaning are essential initial steps in the post-harvest processing of sweet potatoes. These processes help remove dirt, debris, and inferior quality produce, ensuring that only high-quality roots are further processed. Cleaning techniques may vary from simple water rinses to more sophisticated washing systems that reduce microbial contamination. Automated systems for cleaning and grading sweet potatoes are being increasingly adopted to enhance efficiency and reduce labor costs (Abbasov, 2019). Peeling is another important step in preparing sweet potatoes for consumption or industrial processing. Mechanical peeling methods, such as abrasion peeling, are commonly used in large-scale processing plants. These methods help to efficiently remove the skin without causing significant damage to the tuber, which can help maintain the nutritional content and minimize waste (Rashid et al., 2022). Peeling is particularly important in ready-to-eat and processed products where the outer skin is less desirable for consumers. 3.2 Drying, storage, and processing methods Drying is a widely used post-harvest method to extend the shelf life of sweet potatoes by reducing their moisture content. Various drying methods are employed, including sun drying, hot-air drying, and advanced techniques like vacuum and freeze drying. Sun drying, although cost-effective, is prone to contamination and nutrient loss. In contrast, advanced drying technologies such as freeze-drying and vacuum drying help retain more nutrients, such as beta-carotene and phenolic compounds, improving the nutritional value of the final product (Savas, 2022). Storage conditions play a critical role in maintaining the quality of sweet potatoes. Proper storage helps to minimize physiological weight loss, sprouting, and microbial decay. Techniques such as the use of ventilated storage bags and improved traditional platforms have shown positive results in reducing spoilage, particularly under challenging storage conditions in tropical climates (Richard et al., 2023). Studies show that the combination of infrared drying (IR) and hot air drying (HAD) can significantly reduce drying time, lower energy consumption, and maintain the integrity of the product's color and microstructure (Figure 1) (Rashid et al., 2022). The use of curing before storage-where harvested sweet potatoes are exposed to high humidity and moderate temperatures-helps to heal minor wounds, reducing post-harvest decay and enhancing storability (Sugri et al., 2019). 3.3 Effects of storage conditions on sweet potato quality (e.g., sugar and starch content) Storage conditions significantly affect the quality of sweet potatoes, particularly their sugar and starch content. During storage, enzymatic activities cause changes in the starch and sugar levels. Under improper storage conditions, sweet potatoes can experience rapid starch degradation, leading to an increase in sugar content. This change impacts the texture and flavor, making the sweet potatoes sweeter and softer (Kwarteng et al., 2020). Research has shown that prolonged storage at optimal temperatures (around 13-15°C) can maintain the balance between starch and sugar, preserving the overall quality of the tubers. Additionally, delayed harvesting has been found to induce the accumulation of bioactive compounds, such as carotenoids, which enhance the nutritional value of the sweet potatoes (Simões et al., 2020). However, excessively long storage or improper temperature control can lead to undesirable texture changes and nutrient loss.
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