Quality Improvement of Semi-Wet Terasi by Optimizing the Starter Culture Ratio of Controlled Fermentation

Terasi is a traditional fermented shrimp paste used in Indonesian dish as condiments. Due to its affordability, the paste is widely consumed among the general population, and thus has a great impact in Indonesia. Currently, small-scale or home industry is common for terasi production, and natural fermentation process is the traditional method. Fermentation process is considered complete when desired aromatic odors are obtained. However, this makes the fermentation process subjective, because the decision is solely dependent on the producer. Additionally, natural fermentation poses a higher risk for contamination of microbial pathogens. As a result, the quality of the final product varies greatly from region to region. Therefore, it is necessary to improve the quality of terasi by means of controlled fermentation. Hence, the objective of the research is to optimize the controlled fermentation condition of terasi by determining the most optimal ratio of mixed starter culture. Optimal fermentation conditions were determined by analyzing the effect of the various starter inoculum on the inner microbial community, and results indicated that mixed culture of Staphylococcus saprophyticus, Bacillus subtilis, and Lactobacillus murinus with ratio of 2:1:2 was the most effective for suppressing the growth of unwanted microorganisms. The difference in the microbial composition also resulted to a change in the metabolite profile of terasi

Comparison Between the Potential of Tempe Flour Made from Germinated and Nongerminated Soybeans in Preventing Diabetes Mellitus

This study was aimed to compare the chemical characteristics of tempe flour made from nongerminated soybean (NST) and germinated soybean (GST), especially on their capacity in preventing diabetes mellitus (DM). Soybeans were germinated for 20 hours in the dark until 2.5-5.0 mm of the radicle emerged. The ungerminated soybeans and the germinated soybeans were then processed into tempe and tempe flour. The two types of tempe flour were subjected to proximate analysis, amino acid profiling, antioxidant capacity, total phenol content, isoflavone content, and α-amylase and α-glucosidase enzyme inhibition analyses. GST was superior in preventing DM in the protein content and antioxidant parameters, as these were significantly higher (p<0.05) than in NST. On the other hand, NST was superior in preventing diabetes in the isoflavon (daidzein, genistein, and total isoflavone) and α-amylase inhibition IC50 parameters which were significantly better (p<0.05) than in GST. On the contrary, the diabetes-preventing parameters total phenols, α-glucosidase inhibition IC50, and insulinotropic amino acids (arginine, alanine, phenilalanine, isoleucine, leucine, and lysine) were not different (p>0.05).  Therefore, GST and NST both have potential in preventing diabetes through different mechanisms

Identification of potential quality markers in Indonesia’s Arabica specialty coffee using GC/MS-based metabolomics approach

Introduction: The cupping test is a widely used method for quality assessment of Arabica coffee. However, the cupping test is limited by the low number of certified panelists and the low throughput. Therefore, an analytical-based quality assessment may be a promising tool to complement the cupping test. A present, there is no report investigating quality marker candidates, focusing only on “specialty” grade Arabica coffee from Indonesia. Objective: This study identified the potential quality marker(s) in Arabica Specialty coffee at different stages (green beans, roasted beans, and brewed coffee. Methods: The metabolite profiles of ten different Arabica specialty-grade coffees were analyzed with different cup scores using gas chromatography–mass spectrometry (GC/MS). From the ten samples, green coffee beans, roasted coffee beans, and brewed coffee were selected. In addition, an orthogonal projection to latent structure (OPLS) regression analysis was conducted to obtain a potential quality marker based on the variable importance in projection (VIP). The potential quality marker(s) were validated by GC/MS metabolome profiling and OPLS analysis of different sets of samples consisting of 35 Arabica specialty-grade coffee samples. Results: In Arabica coffee samples, the OPLS model of the three stages showed galactinol to have a high VIP score. Galactinol showed a consistent positive correlation with cup scores at all stages of coffee production (green beans, roasted beans, and brewed coffee). The correlation suggests galactinol is a potential quality marker after further validation using different samples. Conclusion: GC/MS combined with OPLS regression analysis suggested galactinol as a quality marker and provide an early screening method for Arabica coffee quality that complements the cupping test performed by certified panelists.The version of record of this article, first published in Metabolomics, is available online at Publisher’s website: https://doi.org/10.1007/s11306-023-02051-

The Effect of Feed Supplementation with Fermented Red Seaweed (Kappaphycus alvarezii) on Growth and Survival of White Shrimp (Litopenaeus vannamei) Post-Larvae Culture

This study was aimed to investigate the effect of novel shrimp diet supplemention with fermented red seaweed Kappaphycus alvarezii on growth and survival of whiteleg shrimp (Litopenaeus vannamei) post-larvae culture. The research consisted of three consecutive steps: (1) preliminary study on Kappaphycus alvarezii fermentation, (2) feed formulation and proximate analysis, (3) performance test of commercial feed (C), commercial + 0.5% K. alvarezii (EF1), and commercial + 1.5% fermented K. alvarezii (EF2). Following 15 days of feeding, the highest biomass, specific growth rate and survival were achieved in EF2 treatment (1.60±0.21 g, 10.88±0.86%/d, 91.67±1.53%), significantly different from control (0.99±0.09 g, 7.72±0.63%/d, 47.00±5.00%) (p<0.05). Overall, this study suggested that the dietary supplementation of 1.5% fermented K. alvarezii can enhance the growth and survival of whiteleg shrimp during the nursery phase

Quantitative HPLC and FTIR-based metabolomics for clustering Centella asiatica cultivation ages and evaluation of their radical scavenging activity

Centella asiatica is a medicinal plant used to treat stomachache, cough, sore throat, blood booster, and skin diseases. The difference in harvesting time is among the factors that can significantly affect the chemical composition of C. asiatica. The purpose of this study was to evaluate the difference of C. asiatica cultivation ages through a metabolomics (targeted and untargeted) analysis using FTIR spectra, HPLC analysis of four main components, and evaluation of its radical scavenging activity. The results showed that differences in cultivation ages affected the chemical composition of C. asiatica. It was shown by the FTIR spectrum indicating the vibration of several functional groups such as OH, C-H, C=O, C=C, C-O, C-N, C-O phenol, and alkyl halides with differences in their intensities. The results of the HPLC showed that C. asiatica harvested after four months post-planting (MPP) had the highest content of madecassoside, asiaticoside, madecassic acid, and asiatic acid, respectively. A principal component analysis (PCA) was carried out to clustering C. asiatica based on its cultivation ages. The PCA results showed that each sample could be grouped with a total variance of the first two principal components (PC) using peak are of the four main components analyzed by HPLC and absorbance at wavenumber 400-4000 cm-1 from FTIR spectra were 98% and 95%, respectively. The radical scavenging activity demonstrated that the 4 MPP had the highest inhibition of about 53.81±0.92 %. So, C. asiatica at 4 MPP gave optimum level four main metabolite content and radical scavenging activity

Metabolomic Analysis of Response to Nitrogen-Limiting Conditions in Yarrowia spp.

Yarrowia is a yeast genus that has been used as a model oleaginous taxon for a wide array of studies. However, information regarding metabolite changes within Yarrowia spp. under different environmental conditions is still limited. Among various factors affecting Yarrowia metabolism, nitrogen-limiting conditions have a profound effect on the metabolic state of yeast. In this study, a time-course LC-MS/MS-based metabolome analysis of Y. lipolytica was performed to determine the optimal cultivation time and carbon-to-nitrogen ratio for studying the effects of nitrogen-limiting conditions on Yarrowia; we found that cultivation time of 36 h and carbon-to-nitrogen ratio of 4:1 and 5:0 was suitable for studying the effects of nitrogen-limiting conditions on Yarrowia and these conditions were applied to six strains of Yarrowia. These six strains of Yarrowia showed similar responses to nitrogen-limiting conditions; however, each strain had a unique metabolomic profile. Purine and pyrimidine metabolism were the most highly affected biological pathways in nitrogen-limiting conditions, indicating that these conditions affect energy availability within cells. This stress leads to a shift in cells to the utilization of a less ATP-dependent biological pathway. This information will be beneficial for the development of Yarrowia strains for further scientific and industrial applications

Effects of Soaking Tempe in Vinegar on Metabolome and Sensory Profiles

Tempe is a fermented soybean food that is globally renowned for its high protein content. Methods of preparing tempe vary worldwide, and include soaking in vinegar before fermentation. This study aimed to determine the effects of soaking in vinegar by metabolome analysis, gas chromatography/mass spectrometry, and sensory attribute evaluation. Vinegar affected metabolism during tempe fermentation, which led to altered metabolite profiles in the final product. We validated the metabolite profiles of two types of tempe using triangle tests and rate-all-that-apply (RATA) tests, which revealed that the sensory attributes of a golden-brown color, ammonia smell, pleasant smell, salty flavor, and acceptance significantly differed (p < 0.05) between the two types of tempe. A high concentration of specific amino acids in the control tempe explained a strong ammonia smell, saltiness, and darker golden-brown sensory attributes. Tempe soaked in vinegar contained high concentrations of metabolites associated with a roasted aroma and cooked meat. In conclusion, most RATA panelists who were being introduced to tempe preferred that soaked in vinegar to the control that was not

Metabolomics-Based Study of the Effect of Raw Materials to the End Product of Tempe—An Indonesian Fermented Soybean

Tempe is a fermented soybean food from Indonesia, made by inoculating Rhizopus spp. onto cooked and dehulled soybean. Tempe has been a part of Indonesian culture since the 16th century and is now produced globally as a highly nutritious plant-based food. Despite a longstanding history on the production of tempe, very few studies have been reported to understand the effect of raw material to the end product metabolite composition. In this research, we applied GC/MS-based metabolite profiling to investigate the effect of various possible factors that might affect the final product (environmental factors, raw materials, and starter cultures). Representative samples were tempe produced by Indonesian industries, Japanese industries as well as laboratory made tempe. The results showed that both environmental factors and raw materials (soybean, water, and starter culture) contributed to the tempe metabolite profile. Here we found the possibility that starter cultures might play a greater role to determine the metabolite profiles compared to other tested factors. This research might provide useful insights for the larger scale industries to maintain the quality of tempe for the benefit of the consumers