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Rambutan seeds are by-products generated from fruit-processing factories; the leftover seeds are buried in landfills, generating methane emissions. This work aimed to extract polysaccharides (POLS) from rambutan seeds by using subcritical water extraction (SWE). The effects of defatting pretreatment and operating parameters in SWE were investigated using a Box–Behnken design. The results show that defatting pretreatment significantly enriched the POLS yield, while it had no significant effect on the total sugar content. Using the desirability approach, the suitable feedstock for SWE was defatted rambutan seeds. The maximum desirability of 0.86 was found at a temperature range of 145–150 °C, an extraction time of 15 min, and a liquid–solid ratio of 10:1. The POLS yield and total sugar content were in the range of 52.33–55.63 g/100 g feedstock and 83.37–87.45 g/100 g POLS, respectively. The extracted POLS had an equivalent molecular weight of 413.70 kDa that could be used as an extender in plant-based products. In conclusion, the defatting pretreatment of rambutan seeds not only improved the POLS yield obtained via SWE but also generated additional lipids that could be utilized as an unconventional source of specialty fat. [ABSTRACT FROM AUTHOR]

This paper presents the initial exploration of the free radical scavenging capabilities of peptides derived from protein hydrolysates (PPH) obtained from Zingiber cassumunar rhizomes (Phlai). To replicate the conditions of gastrointestinal digestion, a combination of pepsin and pancreatin proteolysis was employed to generate these hydrolysates. Subsequently, the hydrolysate underwent fractionation using molecular weight cut-off membranes at 10, 5, 3, and 0.65 kDa. The fraction with a molecular weight less than 0.65 kDa exhibited the highest levels ABTS, DPPH, FRAP, and NO radical scavenging activity. Following this, RP-HPLC was used to further separate the fraction with a molecular weight less than 0.65 kDa into three sub-fractions. Among these, the F5 sub-fraction displayed the most prominent radical-scavenging properties. De novo peptide sequencing via quadrupole-time-of-flight-electron spin induction-mass spectrometry identified a pair of novel peptides: Asp-Gly-Ile-Phe-Val-Leu-Asn-Tyr (DGIFVLNY or DY-8) and Ile-Pro-Thr-Asp-Glu-Lys (IPTDEK or IK-6). Database analysis confirmed various properties, including biological activity, toxicity, hydrophilicity, solubility, and potential allergy concerns. Furthermore, when tested on the human adenocarcinoma colon (Caco-2) cell line, two synthetic peptides demonstrated cellular antioxidant activity in a concentration-dependent manner. These peptides were also assessed using the FITC Annexin V apoptosis detection kit with PI, confirming the induction of apoptosis. Notably, the DY-8 peptide induced apoptosis, upregulated mRNA levels of caspase-3, -8, and -9, and downregulated Bcl-2, as confirmed by real-time quantitative polymerase chain reaction (RT-qPCR). Western blot analysis indicated increased pro-apoptotic Bax expression and decreased anti-apoptotic Bcl-2 expression in Caco-2 cells exposed to the DY-8 peptide. Molecular docking analysis revealed that the DY-8 peptide exhibited binding affinity with Bcl-2, Bcl-xL, and Mcl-1, suggesting potential utility in combating colon cancer as functional food ingredients. [ABSTRACT FROM AUTHOR]

Rambutan seeds (RS) are industrial waste often generated in the canned fruit industry. The aim of this study was to extract polysaccharides from defatted rambutan seeds or crude polysaccharides (POLS-DRSs) with subcritical water. Defatted seed powder (DRS) was extracted by hot-water extraction (HWE) at 100 °C as a reference condition. Subcritical water extraction (SWE) was performed at 120–140 °C and an initial pressure of 2 MPa. A sample-to-water ratio of 1:10 (w/w) and an extraction time of 15–60 min were used for both methods. The results show that gravimetric extraction yields of 53.01 g/100 g DRS and 7.71–41.70 g/100 g DRS were obtained from HWE and SWE, respectively. Additionally, HWE provided a total sugar content of 30.75 g/100 g POLS-DRSs, while SWE generated a total sugar content in the range of 27.00–49.76 g/100 POLS-DRSs. The antioxidant activities of POLS-DRSs were measured with a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. An amount of 40 mg of POLS-DRSs obtained at 120 °C after 60 min provided the highest DPPH activity of 82.93% inhibition. The POLS-DRSs were suitable for growing microorganisms because they had a high sugar content and a low total phenolic content. A prebiotic activity assay will be carried out in future studies. [ABSTRACT FROM AUTHOR]

Spent coffee grounds (SCGs) are currently considered abandoned landfill waste despite retaining valuable organic compounds, especially with a high protein content of 16.64 ± 0.13 g/g dried SCGs and a high oil content of 15.48 ± 0.17 g/g dried SCGs. As a result, SCGs could serve as a potential source of valuable ingredients. However, utilizing a single technical strategy of alternative green extractions was insufficient for extracting the target compounds and hydrolyzing proteins. This work aimed to optimize the operating parameters of enzyme-assisted extraction (EAE), microwave-assisted extraction (MAE), and subcritical water extraction (SWE) using a response surface methodology. The results showed that EAE, at a papain-to-substrate ratio (E/S) of 0.5 and a duration of 15 min, generated a %DH of 93.39% and provided a water soluble protein concentration (WSPC) in the range of 400 to 800 µg/mL. Moreover, MAE provided a maximum %DH of 9.72% at 600 watts and 10 min, while SWE produced a maximum %DH of 13.41% at 160 °C in 17.5 min. However, the WSPCs of MAE and SWE extracts were comparable at ~250 µg/mL. The combination MAE−SWE enhanced the %DH of hydrolysates by more than the combined SWE−MAE, SWE, and MAE. However, the effects of differential hydrolysis on bioactivity are not directly correlated with %DH. In this study, the highest antioxidant activity was found at an E/S of 0.5 and in 15 min for EAE, at 350 W and in 10 min for MAE, and at 160 °C and in 30 min for SWE. This work demonstrated that the valorization of SCGs not only reduces the amount of waste but also yields functional cosmeceutical and nutraceutical ingredients. [ABSTRACT FROM AUTHOR]