Production of Fish Silages from Fish Entrails and Its Nutritional Evaluation

The study was undertaken to investigate fish entrails (heads, bones, viscera, fins) suitability as raw materials for fish silage production for the fish feed supplement. Two types of fish silages were prepared using pure culture of Lactobacillus as lactic fermentation starter and formic acid as acid fermenter. Lactobacilli was isolated and identified for the preparation of fermentation starter from fresh milk. The starter bacteria and molasses were added to minced raw materials in three different compositions to produce three fermented silages and 3% formic acid was used for acid silage production. Biochemical changes were monitored continuously during the fermentation of the silages. Non-protein nitrogen concentration increased from an initial value of 19.56% to 42%. The proximate composition of the final products after 80 days of fermentation on dry matter basis showed that acid silage contained higher crude protein (31.25±0.75%) than fermented silages (21±0.54% - 28±1.11%). Crude lipid content didn’t show any significant differences among silages prepared (P>0.5). Most of the essential amino acids were present in fairly good concentration in all the silages which are comparable to those of the FAO/WHO requirement. Protein content and the amino acid profile of the silages suggest that it should be possible to partially replace with fish meal in feeds for fish and animal.

Single and Multiple Inoculum of Lactiplantibacillus plantarum Strains in Table Olive Lab-Scale Fermentations

In order to improve the olives’ quality, and to reduce the de-bittering time during the table olive fermentation process, it is necessary to pilot the fermentation by inoculating the brine with selected cultures of microorganisms. Some probiotic tests, such as resistance/sensitivity to antibiotics, bile salt hydrolase (BSH) activity, growth at acidic pH, an auto-aggregation assay, and a test of the production of exopolysaccharides, were carried out in order to screen 35 oleuropeinolytic Lactiplantibacillus plantarum subsp. plantarum strains to be used in guided fermentations of table olives. On the basis of the technological and probiotic screening, we analyzed the progress of three different lab-scale fermentations of Olea europaea L. Itrana cv. olives inoculated with spontaneous, single, and multiple starters: jar A was left to ferment spontaneously; jar B was inoculated with a strongly oleuropeinolytic strain (L. plantarum B1); jar C was inoculated with a multiple inoculum (L. plantarum B1 + L. plantarum B51 + L. plantarum B124). The following parameters were monitored during the fermentation: pH, titratable acidity, NaCl concentration, the degradation of bio-phenols, and the enrichment rate of hydroxytyrosol and tyrosol in the olive’s flesh, oil and brine. The degradation of secoiridoid glucosides appeared to be faster in the inoculated jars than in the spontaneously-fermented jar. The production of hydroxytyrosol and ligstroside aglycons was high. This indicated a complete degradation of the oleuropein and a partial degradation of the ligstroside. The multiple inoculum ensured a complete debittering, and could give probiotic traits. The presence of L. plantarum B1 and B124 as a fermentation starter guarantees an optimal trend of de-bittering and fermentation variables, thus ensuring the production of a better final product. L. plantarum B51 could be considered to be a promising probiotic candidate for obtaining probiotic food of completely vegetable origin.

Predicting the moisture content of Daqu with hyperspectral imaging

Daqu, a Chinese liquor fermentation starter, contains all kinds of microorganisms and enzymes for Chinese liquor fermentation. The moisture content of Daqu significantly influence on the reproduction of microorganisms in Daqu. This work presents for the first time that determination of moisture content of Daqu with hyperspectral imaging. The characteristic spectrum of water is extracted based on comparative experiments with varying moisture content. The molds based on the full bands and feature bands were established by the support vector regression (SVR) method, which is used to predict moisture content of Daqu during fermentation process. The performance of the model based on the feature bands (R2 = 0.9870, root mean square error (RMSE) = 0.0091) is comparable to the full bands and the dimensions of the spectral information were significantly reduced. This work presents a novel, rapid and nondestructive approach for detecting the moisture content in Daqu and lays a foundation for the application of hyperspectral imaging.

Synergistic Effect of Multiple Saccharifying Enzymes on Alcoholic Fermentation for Chinese Baijiu Production

ABSTRACT Chinese Jiuqu (fermentation starter) provides saccharifying enzymes for baijiu (Chinese liquor) fermentation, which undergoes a simultaneous saccharification and fermentation process. However, the key saccharifying enzymes associated with alcoholic fermentation from Jiuqu and their effects on ethanol production remain poorly understood. In this study, we identified 51 carbohydrate hydrolases in baijiu fermentation by metaproteomics analysis. Through source-tracking analysis, approximately 80% of carbohydrate hydrolases in the baijiu fermentation were provided by Jiuqu. Among these enzymes, alpha-amylase (EC 3.2.1.1) and glucoamylase (EC 3.2.1.3), from Aspergillus, Rhizomucor, and Rhizopus, were positively related to starch hydrolysis and ethanol production, indicating that they were the key saccharifying enzymes associated with alcoholic fermentation in the baijiu fermentation. Moreover, a combined mixture of alpha-amylase and glucoamylase (in a ratio of 1:6, wt/wt) enhanced ethanol production in a simulative baijiu fermentation under laboratory conditions. This result revealed a synergistic effect of multiple saccharifying enzymes on ethanol production in baijiu fermentation. Our study provides a potential approach to improve the efficiency of saccharification and alcoholic fermentation by optimizing the profile of saccharifying enzymes for fermentation of baijiu and other beverages. IMPORTANCE Jiuqu starter provides enzymes to the simultaneous saccharification and fermentation process of baijiu (Chinese liquor) production; however, the key saccharifying enzymes associated with alcoholic fermentation from Jiuqu and their effects on ethanol production remain unclear. We confirmed that Jiuqu was the main source of carbohydrate hydrolases for baijiu fermentation and identified two types of saccharifying enzymes from multiple microbes as the key enzymes associated with alcoholic fermentation. Moreover, a proper combination of multiple saccharifying enzymes could enhance ethanol production in baijiu fermentation. This combination provides an approach to optimize the profile of saccharifying enzymes for enhancing ethanol production in baijiu and other food fermentations.

Bioethanol from Guinea Grass (Panicum Maximum) and Ragi Tempeh as Fermentation Starter using Bioreactor and Shaker

This study was investigating the production of bioethanol from the mixture of guinea grass (Panicum maximum) and using ragi tempeh through fermentation. The acid pretreatment process was carried out using 15% v/v sulphuric acid. The fermentation was carried out in anaerobic condition using bioreactor and shaker at 37°C and different pH of 5,6,7, and 8. Freezing test and Tollens’ test result showed very ethanol concentration in the sample product is very low, and aldehyde compounds are present in the product sample. The aldehyde is released due to degradation of lignocellulosic feedstock by acid hydrolysis. HPLC is carried out for getting a more accurate result. The best result is chromatogram of sample 5, obtained by fermentation using shaker with pH 8. It shows normal chromatogram with ethanol yield of 7.89%.