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With high moisture and sugar content, fresh grapes respire and transpire actively after harvest, which contribute to quality loss. Drying can process grapes into raisins for longer shelf-life as well as dehydrated grapes, which can be used for wines or juice production. The pre-treatments, drying method and drying conditions, can significantly influence the quality of final products. In this chapter, firstly, different pretreatments as a necessary operation previous to the drying of grapes into raisins is introduced. These pre-treatments include chemical pre-treatment, physical pretreatment, and blanching. In addition, the quality and drying characteristics of different pre-treatments is summarized too. Secondly, the current status of different technologies for grape drying and their effects on drying kinetics and quality attributes of seedless grapes are described to highlight the advantages and disadvantages of each drying method. These drying methods include the traditional open sun drying, shade drying, hot-air drying, freezing drying, microwave drying, as well as the vacuum impulsed drying. Thirdly, influences of drying on bioactive substances (flavonoids, phenolics, anthocyanin, and resveratrol) and antioxidant capacity of grape by-products including seed, skin, stem, and stalk are also examined. Finally, the future research trends of grape and its by-product drying are indentified and discussed.

PurposeChinese consumers have increased their consumption of grape products in recent years due to recognition of the nutritional value of grapes. At the same time, consumers are paying more attention to food safety because of the occasional occurrence of food safety scares. Based on a survey of consumers in Zhejiang, China, this paper aims to understand and provide information on consumers' perceptions of quality and safety for grape products, purchasing behavior, and willingness to pay (WTP) for grape products.Design/methodology/approachThis paper presents the results of empirical research. The survey method was a direct (face‐to‐face) interview based on a standardized questionnaire. Consumers' perceptions of the quality and safety of grape products were examined, together with consumers' demographic characteristics.FindingsThe results indicate that quality and safety, rather than price, are considered the most important factors that affect consumers' purchasing decisions for grape products. Consumer's educational level, the average price of grapes and the perception of safety are the main factors that determine consumers' WTP for grape products. As price increases, the consumer's WTP for safe and high quality grapes decreases.Originality/valueThis research provides a chance to understand consumers' demand and WTP for the quality and safety of grape products in Zhejiang, China. Further understanding was gained regarding factors affecting consumers judging grape products, which in turn may influence their purchase decisions. The results also could guide grape growers to supply products that better meet consumers' needs. It is proposed that the Chinese government pay more attention to taking measures to improve the quality and safety of grape products.

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