Faculty of Bioscience and Technologies for Food, Agriculture, and Environment, University of Teramo, Teramo, Italy.
CREA, Research Centre for Olive, Fruit and Citrus Crops, Rome, Italy.
J Food Sci. 2023 Apr;88(4):1308-1324. doi: 10.1111/1750-3841.16487. Epub 2023 Feb 15.
Hop extracts represent a natural alternative to synthetic food additives because of their high content of bitter acids and volatile organic compounds (VOCs) with bittering, flavoring, and antimicrobial properties. However, broader uses of hop extracts as natural techno-functional ingredients rely on the identification of sustainable and affordable extraction technologies allowing to diversify the processes and produce extracts characterized by different compositions and, consequently, qualitative properties. Thus, this study is aimed to evaluate and compare the effect of innovative and conventional extraction methods on the bitter acids content and VOCs pattern of food-grade ethanolic hop extracts for food applications. Innovative extractions were carried out by using two ultrasound systems (a laboratory bath [US] and a high-power ultrasound bath [HPUS]), and a high-pressure industrial process (high hydrostatic pressure [HHP]). Conventional extractions (CONV) were performed under dynamic maceration at 25 and 60°C; for ultrasound and conventional methods, the effect of the extraction time was also investigated. Among the extracts, the highest and lowest content of bitter acids was found in CONV 60°C extracts, and HHP and CONV 25°C extracts, respectively. Of the 34 VOCs identified in dry hops, ∼24 compounds were found in US, HPUS and CONV extracts, while only 18 were found in HHP. CONV extractions showed higher selectivity for sesquiterpenes, while US and HPUS showed higher selectivity for esters and monoterpenes. Hierarchical cluster analysis (HCA) and partial least squares-discriminant analysis (PLS-DA) allowed classifying hop extracts based on the extraction methods and also allowed highlighting the technological conditions to produce hop extracts with specific techno-functional and flavoring properties. PRACTICAL APPLICATION: The study showed that different extraction methods can lead to hop products with varying sensory and functional properties. By selecting the right extraction method, companies can produce hop extracts with specific compositions that meet their needs for clean label and sustainable food products, as well as new edible packaging or coatings.
Hop extracts represent a natural alternative to synthetic food additives because of their high content of bitter acids and volatile organic compounds (VOCs) with bittering, flavoring, and antimicrobial properties. However, broader uses of hop extracts as natural techno-functional ingredients rely on the identification of sustainable and affordable extraction technologies allowing to diversify the processes and produce extracts characterized by different compositions and, consequently, qualitative properties. Thus, this study is aimed to evaluate and compare the effect of innovative and conventional extraction methods on the bitter acids content and VOCs pattern of food-grade ethanolic hop extracts for food applications. Innovative extractions were carried out by using two ultrasound systems (a laboratory bath [US] and a high-power ultrasound bath [HPUS]), and a high-pressure industrial process (high hydrostatic pressure [HHP]). Conventional extractions (CONV) were performed under dynamic maceration at 25 and 60°C; for ultrasound and conventional methods, the effect of the extraction time was also investigated. Among the extracts, the highest and lowest content of bitter acids was found in CONV 60°C extracts, and HHP and CONV 25°C extracts, respectively. Of the 34 VOCs identified in dry hops, ∼24 compounds were found in US, HPUS and CONV extracts, while only 18 were found in HHP. CONV extractions showed higher selectivity for sesquiterpenes, while US and HPUS showed higher selectivity for esters and monoterpenes. Hierarchical cluster analysis (HCA) and partial least squares-discriminant analysis (PLS-DA) allowed classifying hop extracts based on the extraction methods and also allowed highlighting the technological conditions to produce hop extracts with specific techno-functional and flavoring properties. PRACTICAL APPLICATION: The study showed that different extraction methods can lead to hop products with varying sensory and functional properties. By selecting the right extraction method, companies can produce hop extracts with specific compositions that meet their needs for clean label and sustainable food products, as well as new edible packaging or coatings.
啤酒花浸膏是合成食品添加剂的天然替代品，因为它们含有丰富的苦味酸和具有苦味、调味和抗菌特性的挥发性有机化合物（VOCs）。然而，更广泛地将啤酒花浸膏用作天然技术功能性成分依赖于识别可持续且经济实惠的提取技术，以实现工艺多样化，并生产具有不同组成和相应定性特性的提取物。因此，本研究旨在评估和比较创新和传统提取方法对食品级乙醇啤酒花浸膏中苦味酸含量和 VOC 模式的影响，以应用于食品。创新提取采用了两种超声系统（实验室浴[US]和高功率超声浴[HPUS]）和高压工业过程（高静压[HHP]）进行。传统提取（CONV）在 25 和 60°C 下进行动态浸渍；对于超声和传统方法，还研究了提取时间的影响。在提取物中，CONV 60°C 提取物中苦味酸含量最高，HHP 和 CONV 25°C 提取物中苦味酸含量最低。在干啤酒花中鉴定出的 34 种 VOC 中，在 US、HPUS 和 CONV 提取物中发现了约 24 种化合物，而在 HHP 中仅发现了 18 种化合物。CONV 提取对倍半萜烯具有更高的选择性，而 US 和 HPUS 对酯类和单萜烯具有更高的选择性。层次聚类分析（HCA）和偏最小二乘判别分析（PLS-DA）允许根据提取方法对啤酒花提取物进行分类，还允许突出生产具有特定技术功能和调味特性的啤酒花提取物的技术条件。实际应用：研究表明，不同的提取方法可以导致具有不同感官和功能特性的啤酒花产品。通过选择正确的提取方法，公司可以生产出具有特定成分的啤酒花提取物，以满足他们对清洁标签和可持续食品产品以及新的可食用包装或涂层的需求。
