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Bioactive compounds-rich Gac peel powder: Optimization of extraction and foam-mat drying conditions
Author(s)
Thuy, Nguyen Minh
Tien, Vo Quoc
Giau, Tran Ngoc
Van Hao, Hong
Minh, Vo Quang
Van Tai, Ngo
Date Issued
December 1, 2025
Type
Article
Abstract
Gac fruit (Momordica cochinchinensis Spreng) is a healthy fruit and has long been used as food and medicine. During fruit processing, the peel is often discarded as waste. However, Gac fruit peel contains a significant amount of carotenoids. This study encapsulates bioactive compounds extracted from dried Gac peels using egg albumin (EA) and xanthan gum (XG) as foaming agents and stabilizers in foam-mat drying at different temperature. The extraction process (in ethanol 60 %) was assisted by ultrasound (40 kHz, 350 W) with solvent: Gac peel ratios of 30/1–40/1, extraction temperature and time of 45–55 °C and 25–55 min, respectively. EA (9.2–15.2 %) and XG (0.1–0.38 %) were used as foaming agent and foam stabilizer, respectively, with different foam-mat drying temperatures (65–75 °C). The Response Surface Methodology (RSM) combined with a Box-Behnken Design (BBD), 3 factors - 3 levels was used to optimize the independent variables to capture the maximum level of dependent variables. The optimal extraction conditions were determined (solvent/Gac peel ratio of 36.26/1, temperature of 51.38°C and time of 43.39 min) for the extract containing high levels of lycopene 292.04 μg/g, β-carotene (515.72 μg/g) and total polyphenols (3.86 mg GAE/g). The extract was used to produce powder by foam-mat drying. EA, XG and drying temperature significantly affected the drying rate and powder quality. The optimum concentrations of EA and XG were determined to be 13.13 % and 0.3 %, respectively, at an optimum drying temperature of 72.4°C. Under these conditions, the highest drying rate (2.41 g water/g dry matter/min) was achieved to produce powder containing the with highest content of lycopene, β-carotene and total polyphenol contents, 83.42 µg/g, 97.68 µg/g and 1.09 mg GAE/g, respectively. The physical and chemical properties of foam-mat dried Gac peel powder were also investigated. Making good use of byproducts from fruit processing will help local communities and businesses while also ensuring the goal of a circular economy, contributing to long-term socioeconomic growth and enhancing public health, at least in the region and around the world.
Citation
Food and Humanity, 5, 2025