Composition and research progress in processing and application of walnut cake (meal)

China has the largest area of walnut plantation and the highest output of walnuts in the world. In addition to fresh comcumption, the majority of walnuts are used for extracting walnut oil. Walnut cake(meal) is the by-product obtained from walnut oil extraction, which is abundant in essential nutrients such as protein, vitamins, and minerals required by the human body. However, despite its nutritional value, walnut cake (meal) is typically used as a food processing ingredient or livestock feed. Its utilization rate in further processing is low, resulting in limited deep-processing products and low added value. This paper summarizes the main nutrients components in walnut cake (meal) and its current processing and application status. The analysis reveals the challenges related to low utilization rates and high processing costs for walnut cake (meal). It suggests that utilizing cost-effective methods to extract protein from walnut cake (meal) or implementing rational direct processing can address these issues effectively. Ultimately, this paper serves as a theoretical foundation and technical guide for advancing the deep processing of walnut cake (meal) while extending the industrial chain for deep-processing walnuts.