Consumer's growing demand for consumption of “Horchata de chufa”, a Spanish beverage produced from tiger nut tubers, has led to large-scale production of tiger nuts, and its subsequent processing for the food industry. Recent investigations clearly show that tiger nut is a valuable source of stable vegetable oils, rich in monounsaturated fatty acids, and phytosterols as well as high-added value compounds (proteins, carbohydrates, vitamins, minerals and bioactive compounds). Several conventional (Soxhlet) and alternative innovative (SC-CO₂, enzyme, high pressure, etc.) extraction methods have been developed for the efficient recovery of tiger nut oil and high-added value compounds. Moreover, several authors have shown the potential of tiger nuts by-products in the development of new healthier and functional products such as fiber rich and oxidative stable foods. The present review provides an overview of these investigations and tries to expose potential avenues for future research in commercial exploitation of tiger nuts and its by-products.

Industrial relevance

Tiger nuts and their by-products obtained from “horchata de chufa” manufacturing process have a remarkable content of nutrients, fiber and bioactive compounds (eg. polyphenols). Moreover, they have a high amount of oil, rich in monounsaturated fatty acids, tocopherols, and phytosterols, thus being a valuable source to be incorporated into different food matrices in order to modify their technological and functional properties.

At this stage of development, tiger nuts by-products are underutilized at an industrial level. For example, the literature about the oil extraction from tiger nuts by-products is scarce and most of the studies have been focused on the use of conventional (Soxhlet) extraction of oil. This review provides an overview of some of the most relevant innovative processing technologies to allow the industrial sustainability and green recovery of oil from tiger nuts and their by-products and, tries to expose potential avenues for future research in commercial exploitation of tiger nuts and its by-products as source of ingredients to be incorporated in new food matrices to improve their technological and functional aspects.

中文翻译：

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老虎坚果及其副产品的增值：从石油和有价值的化合物的提取到开发新的健康产品

消费者对使用虎眼坚果块茎生产的西班牙饮料“ Horchata de chufa”的消费需求不断增长，导致了虎眼坚果的大规模生产及其随后的食品工业加工。最近的研究清楚地表明，老虎坚果是稳定的植物油的宝贵来源，富含单不饱和脂肪酸，植物甾醇以及高附加值的化合物（蛋白质，碳水化合物，维生素，矿物质和生物活性化合物）。几种常规（索氏）和替代性创新（SC-CO ₂，酶，高压等）提取方法已被开发出来，以有效地回收虎油和高附加值化合物。此外，几位作者已经表明了虎果副产品在开发新的更健康和功能性产品（例如富含纤维和氧化稳定的食品）中的潜力。本综述概述了这些调查，并试图为老虎坚果及其副产品的商业开发揭露未来研究的潜在途径。

行业相关性

从“ horchata de chufa”制造过程中获得的老虎坚果及其副产品含有大量营养素，纤维和生物活性化合物（例如多酚）。而且，它们具有大量的油，富含单不饱和脂肪酸，生育酚和植物甾醇，因此是掺入不同食品基质中以改变其技术和功能特性的宝贵来源。

在发展的这一阶段，老虎坚果副产品在工业水平上未被充分利用。例如，关于从老虎坚果副产物中提取油的文献很少，并且大多数研究都集中在常规（索氏提取）油的使用上。这篇综述概述了一些最相关的创新加工技术，以使工业上的可持续发展和从老虎坚果及其副产品中绿色回收石油，并试图为老虎坚果及其坚果的商业开发提供未来的潜在途径。副产品作为成分的来源将被添加到新的食品基质中，以改善其技术和功能方面。