roteins hydrolyzed from melinjo seeds (Gnetum gnemon) at green (GM), yellow (YM) and red (RM) stages of maturity were studied for their effectiveness in antioxidant and antidiabetic activities. The seed protein extract was hydrolyzed using alcalase 2.4L, and the resulting hydrolysates with the highest degree of hydrolysis, protein profile, and the most potent contributors to antioxidant and invitro antidiabetic activities were identified. The degree of hydrolysis value of hydrolysates ranged from 52-84%, and the SDS-PAGE protein profile showed two distinct bands in which the band with molecular weight of 30 kDa degraded more intensively. Antioxidant capacity was measured using different standard methods, including radical cation 2,2-azinobis-(3-ethylbenzothizoline-6-sulphonate) (ABTS•+) assay, hydroxyl radical (OH•), and superoxide anion (O2•-) scavenging. The green hydrolysate (GMH) had significantly higher (p<0.05) free radical scavenging (ABTS•+, OH•, and O2•-) activities than that of the yellow hydrolysate (YMH) and red hydrolysate (RMH). However, invitro antidiabetic testing was performed based on the inhibitory activity of α-amylase and α-glucosidase. GMH was found to be more effective than YMH and RMH. These results showed that the antioxidant and antidiabetic activity in hydrolyzed GM protein has high potential to be utilized as natural nutraceuticals.

Chlorophyll is a natural coloring agent that has antioxidant activity. During the extraction and food processing process, chlorophyll is easily degraded and derivatized. The derivatization process results in changes in the chemical structure of chlorophyll which can result in a change in color and its antioxidant activity. The other extracted minor compounds can affect its antioxidant activity. This study aimed to identify the chemical structure changes of chlorophyll extracted from pandan (Pandanus amaryllifolius Roxb) leaves as affected by the derivatization process and evaluate the antioxidant activity of the extracts and fractions of chlorophyll and its derivatives. Chlorophyll was extracted from pandan leaves with acetone, derivatized, and then purified by fractionation using column chromatography. Chlorophyll extract and its derivatives were analyzed for total carotenoid, total phenolic, and flavonoid contents. The antioxidant activity of extract and fraction was measured by the inhibition of peroxidation of linoleic acid, radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing/ antioxidant power (FRAP) ability, and metal chelating assay. Based on the FTIR and MS/MS spectra, it was observed that the first derivatives were pheophytin and chlorophyllide, while the second derivative was pheophorbide. The other extracted compounds, including phenolic compounds, flavonoids, and carotenoids, might enhance the antioxidant activity of the chlorophyll derivatives. The inhibition rate of linoleic acid peroxidation by chlorophyll, chlorophyllide, and pheophorbide extract was not significantly different from BHT, where pheophytin extract was lower. The radical scavenging activity of DPPH and FRAP assay showed that chlorophyll and chlorophyllide extracts exhibited higher activity, followed by pheophytin and pheophorbide. Meanwhile, the metal chelating assay showed that chlorophyllide fraction exhibited the lowest activity. Therefore, the antioxidant activity of the first derivatives of chlorophyll was higher than the second derivatives. In general, the extract of chlorophyll and its derivatives exhibited higher antioxidant activity than that of their fraction.

The synthetic of antioxidant peptides from melinjo (Gnetum gnemon) seed protein isolated using sol-gel immobilized alcalase was studied, a commercial alcalase was physically entrapped in sol-gel matrices system. Characteristics of protein hydrolyzed were evaluated by the degree of hydrolysis obtained (DH) and the peptide profile by FPLC and SDS-PAGE. The antioxidant activity of protein hydrolyzed was determined using ABTS cation, DPPH, and superoxide radical scavenging assays. The DH values increased very quickly during the second hour followed by a slow increase up to 12 hours. Melinjo seed protein isolated was hydrolyzed about 23% of degree hydrolysis at 50°C after 2 hours of incubation. Similar results were also obtained by FPLC and SDS-PAGE, the peptide profile indicated the sol-gel immobilized alcalase was produced of peptides with low molecular weight from melinjo seed protein isolated. Immobilized alcalase preserved the initial activity over 4 cycles of repeated use in a routine reaction. The ABTS assay, the hydrolysate presented a more than 5 times greater activity than non-hydrolyzed melinjo seed protein isolated. It's confirming the potential use of sol-gel immobilized alcalase in synthetic antioxidant peptides from melinjo seed protein isolated.

The effect of germination on free radical scavenging activities and Angiotensin I-Converting Enzyme (ACE-I) inhibitory of melinjo (Gnetum gnemon) seed proteins was studied to determine its potential use as a nutraceutical ingredient. Investigations into the protein profiles, amino acid composition, free radical scavenging activities and ACE-I-inhibitory of proteins extracted from melinjo seed during germination (0 to 21 days) were carried out. The concentration of amino acids detected in the melinjo seed samples ranged from 0.30 to 12.75 g/100 g protein and the degree of hydrolysis during germination at 21st days was significantly highest than that of either (0-14 days). Furthermore, with all samples a large small-sized peptides degree (