Optimization of germination and ultrasonic‐assisted extraction for the enhancement of γ‐aminobutyric acid in pumpkin seed

Abstract

Germination and ultrasonic‐assisted extraction (UAE) are economical and effective methods to enhance bioactive compounds in plant seeds. We optimized the germination parameters and UAE parameters by using response surface methodology to maximize the recovery of γ‐aminobutyric acid (GABA) in pumpkin seeds. The optimal germination conditions were as follows: soaking the seeds at 28°C for 6 h with 0.2% CaCl2, 3.8 mg/ml monosodium glutamate, and 4.0 mg/ml vitamin B6, then germination at 30°C for 61.6 h. The optimal conditions for UAE were as follows: 1:75 (w/v) material‐to‐solvent ratio, 220 W ultrasonic power, and ultrasonic treatment at 50°C for 14.4 min, which afforded an extraction yield of 2679 ± 10 mg/100 g. Moreover, the GABA‐enhanced extract showed the potential of hypolipidemic effect in type 2 diabetes rats. These results confirmed that a combination of germination and UAE increased the GABA yield from pumpkin seeds and provided a basis for GABA‐enhanced production to improve lifestyle‐associated diseases.

Ultrasound‐assisted extraction of oilseeds—sustainability processes to obtain traditional and non‐traditional food ingredients: A review

“…Moreover, in chia seed surface treatments, it was also observed that the US waves favored the progressive separation of the mucilage fibers from the seed surface (Figure 3), which increased the extraction yield (Wang et al., 2022). US application can additionally have some chemical effects on the different oilseed compounds that could affect product quality, such as free radical and hydrogen peroxide formation (Mwaurah et al., 2020), protein structural changes (Du et al., 2021; Liang et al., 2022; Naik et al., 2022), and antioxidant compounds degradation (Rojas et al., 2021). However, there are studies that have demonstrated the maintaining of oil quality (Hernández‐Santos et al., 2016; Mohammadpour et al., 2019; Samaram et al., 2014; Senrayan & Venkatachalam, 2020), a high antioxidant activity of extracts (Mahindrakar & Rathod, 2020; Savic & Gajic, 2021; Solaberrieta et al., 2022), and the improvement of some functional properties of proteins (Du et al., 2022; Flores‐Jiménez et al., 2019; Naik et al., 2022) when US has been applied.…”

“…Moreover, US wave propagation is less hindered as the solvent to seed ratio increases, thus the wave energy dissipation distance can reach longer distances and temperature can be better controlled. Therefore, it is not surprising that high solvent to seed ratios have resulted in high yields, which were essential to obtain the temperature and time reductions mentioned above (Jalili et al., 2018; Liang et al., 2022; Mahindrakar & Rathod, 2020; Massa et al., 2019; Mohammadpour et al., 2019; Quiroz et al., 2019; Samaram et al., 2015; Wang & Wei, 2015). It is important to note that maximizing product yield during conventional solvent extraction at a continuous industrial scale is commonly used at the highest possible temperature and the lowest possible solvent to solid ratio.…”

“…On the other hand, similar or slightly lower oil and protein yields have been reported by using UAE compared to MAE, conventional extraction, and PLE (Guzmán‐Lorite et al., 2022; Isopencu et al., 2019; Zhong et al., 2018). However, in another research significantly higher protein extraction rate and yield were obtained using UAE instead of MAE and conventional extraction (Liang et al., 2022). Moreover, both techniques showed comparable results in terms of phenolic compounds, flavonoids, and anthocyanins extraction from peach fruit wastes including seeds (Plazzotta et al., 2020).…”

“…Therefore, a more systematic experimental evaluation would be required to explain the observed behaviors. However, at optimized extraction conditions, a shorter UAE time was achieved than that obtained by MAE (Isopencu et al., 2019; Liang et al., 2022). Regarding the quality of products obtained by UAE or MAE, significant differences were not obtained when compared to the conventional extraction in terms of fatty acids and acylglycerol profiles, oxidative stability, thermal properties, and antioxidant compound activities of oils (Zhong et al., 2018).…”

Utilization of pumpkin, pumpkin powders, extracts, isolates, purified bioactives and pumpkin based functional food products: A key strategy to improve health in current post COVID 19 period: An updated review

“…Bioactive compounds, especially γ-aminobutyric acid in pumpkin seeds was enhanced by optimizing the germination parameters and ultrasonic assisted extraction, the economical and effective methods for optimal extraction yield of bioactives. These medicinal food components are associated with reduced risk of lifestyle-associated diseases like diabetes hyperlipidemia ( Liang et al, 2022 ). Pumpkin seed oil due to its nutritional value acquires high market value and is occasionally adulterated with cheaper oils especially sunflower oil.…”