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Rusip is a spontaneously fermented anchovy product originating from Bangka Belitung province in Indonesia, used as umami seasoning. This study investigated the characteristics of rusip and its umami fractions to reveal umami peptides in rusip. Six commercial rusip samples from Bangka were analyzed for their proximate composition, pH, total titratable acids, NaCl, total sugars, free glutamic acid, nucleotide (adenosine monophosphate), and total amino acid composition. Umami taste intensity of water-soluble extracts (WSE) was analyzed by a sensory panel. Total plate count and total lactic acid bacteria were also analyzed to assess the microbial variations between the samples. Stepwise ultrafiltration on the highest umami intensity WSE was conducted to obtain three fractions: >5 kDa, 3-5 kDa, and <3 kDa, followed by chromatography fractionation of fraction <3 kDa by Sephadex G-15 gel to acquire umami fractions (F1-F4). Protein (28.94%-44.53% dry weight basis [db]) and NaCl (30.86%-55.73% db) were the major solids of rusip. Concentrations of free glutamic acid (5.79%-8.99% db) in rusip are related with umami intensities of WSE. F1 was the umami fraction with its residual umami amino acids higher than its free ones; therefore, F1 was also a peptide fraction. It contained peptides of 3-12 residues within the highest relative area. Their sequences contained those of umami peptides listed in BIOPEP database. Some of these peptides were also associated with bioactivities. This information could broaden the insight of umami peptides and their bioactivities in fermented foods. PRACTICAL APPLICATION: Rusip is used as a source of umami ingredient in food. The characteristics of product quality of rusip were reported in this study. In addition, the chemical and sensory characteristics as well as peptides of its umami fraction were also described. This information is important for the exploration of umami peptides from fish fermented products., (© 2024 Institute of Food Technologists.)

Terasi is an Indonesian shrimp paste that is traditionally fermented and is widely consumed by Indonesian people. Terasi is produced by utilizing endogenous bacteria from raw materials as starters. Due to the variation in endogenous bacteria during production, terasi of varying quality is produced. The objectives of this study were to investigate the effects of starters on the physicochemical and sensory properties of terasi. The effects of individual or combination inoculation of Lactobacillus plantarum SB7 and Bacillus amyloliquefaciens BC9 were compared to those of noninoculation during a two-week period of terasi production. The starters darkened the color of the terasi. The terasi produced with the starters had higher protein contents (62.93-64.80 %) than those of the noninoculated terasi (63.66-65.80 %). Although proteolysis was weakly affected by the starters, the starters reduced the terasi fermentation period. The combination starter inoculation resulted in a high glutamic acid level (44284.8 ± 231.22 mg/kg). Volatile alcohols were more abundant in the starter-inoculated terasi than in the noninoculated terasi. Assessments of the sensory parameters by panelists suggested a preference for inoculated terasi. In conclusion, the addition of starters (L. plantarum SB7 and B. amyloliquefaciens BC9) in terasi production improved the physicochemical and sensory properties of the terasi., (Copyright © 2020 Elsevier GmbH. All rights reserved.)

Red oncom, a fermented product from solid waste of soybean curd process, and black oncom, a similar fermented product but made from defatted peanut cake, have been known to have umami taste. Umami fractions of red oncom and black oncom that are responsible for umami taste have not been investigated yet. The objective of this research was to characterize umami fractions obtained by ultrafiltration and chromatography of both oncoms. The first step, water-soluble extracts of oncoms were ultrafiltered using a membrane with cutoff 3,000 Da and followed by gel filtration chromatography (Sephadex G-25) to obtain umami fractions. Ultrafiltration fractions of red oncom (molecular weight [MW] less than 3,000 Da) and black oncom (MW more than 3,000 Da) had an intense umami taste. The further fractionation by gel filtration chromatography linked to taste dilution analysis yielded umami fractions. Chemical characterization revealed that free glutamic acid, free phenylalanine, and peptides containing their residual amino acids were present in the fractions. PRACTICAL APPLICATION: Umami fractions of red and black oncoms can be used as a source of umami compounds for food industries and food services. The information from this paper can be used by other researchers who will explore umami peptides., (© 2020 Institute of Food Technologists®.)

Salted fermented fruit known as asam sunti (Averrhoa bilimbi L.) in Indonesia has been used as a source of umami taste. This study was aimed to characterize the three types of asam sunti and their water soluble extracts, and to trace the compounds responsible for umami taste in umami fractions. Umami fractions were obtained by ultrafiltration followed by Sephadex G-15 chromatographic separation. The three types of samples could be differentiated by physicochemical and sensory analyses. Low molecular weight fraction had the highest umami intensity. Further chromatographic separation revealed three umami fractions, F-II, III and IV. Umami taste of F-III was due to the presence of free l-glutamic acid at 6 times, while FII and FIV were due to succinic acid at more than 30 times their respective umami thresholds. Organic acid as well as amino acid seemed to play an important role in the intense umami taste of asam sunti., (Copyright © 2018 Elsevier Ltd. All rights reserved.)