Physiochemical Properties, Volatile Compounds and Sensory Evaluation of Chili Sauce Shrimp Paste from Different Regions in Indonesia

Chili sauce shrimp paste (CSSP) is an exotic traditional sauce prepared using mainly fresh chili and shrimp paste well known as sambal terasi (Indonesia) and sambal belacan (Malaysia and Brunei). This study aims to evaluate CSSP from different regions in Indonesia on physiochemical properties, volatile compounds, and sensory evaluation. Evaluation in free amino acid (FAA) and volatile compounds were analyzed using HPLC and GC-MS. CSSP had no significant (p > 0.05) on proximate (except for moisture), salinity, pH, microbial counts and the redness index (a*/b*) compared to control. The identified volatiles can be grouped into hydrocarbon, carbonyl, sulfur, alcohol, nitrogen, fatty acid, and ester compounds. The CSSP A, B, C, D, and E (control) contained 9, 21, 12, 29, and 6 volatile compounds respectively. The total FAA ranged from 44.32 to 67.03 g/100 g, and histidine (his) was found as the most abundant in each CSSP. The rheological properties (yield stress, viscosity, and consistency) of CSSP and control values were significantly, except for CSSP B. The intensities perceived of saltiness, sweetness, and bitterness were greatly varied among CSSP. Although there is no correlation between sweetness and bitterness this is indicated by the negative correlation.

Development and Quality Analysis of Protein Enriched Instant Soup Mix

The aim of the study was to develop protein enriched instant fish soup mix and analysis of the quality of various conditions. The study used a mechanical dryer for maintaining a constant air flow and temperature at its drying and dehydration stage. Powder was made after drying. An appropriate composition was used as an indicator. Various compositions like 75%, 65%, 55% and 45% fish powder were used as formulation 0, formulation 1, formulation 2, and formulation 3 respectively. Then these were reconstituted by boiled water for soup mix preparation. The result indicated that mixer 2 was the best composition. The finding suggested that 55% fish powder mix is the best composition for protein enriched instant soup mix. It will help to produce the instant soup mix and an alternative source of various costly animal and plant protein as a value-added material.

Contribution of mixed commercial starter cultures to the quality improvement of fish-chili paste,a Chinese traditional fermented condiment

This study evaluated the effects of commercial starter cultures on the microbial counts,protein degradation,biogenic amines and volatile compounds in fermented fish-chili paste.Four inoculated groups with different starter cultures and one group without inoculation were investigated.The results revealed that the application of mixed starter cultures promoted the growth of lactic acid bacteria and yeast,while effectively inhibited the Enterbacteriaceae counts compared with the spontaneously fermented group.The inoculation with mixed starter cultures resulted in higher levels of umami-tasting free amino acids(FAAs)in all inoculated groups.Highest content of sweet-tasting FAAs was found in group HS(Pichia anomala+Staphylococcus xylosus+Staphylococcus carnosus+Pediococcus pentosaceus+Pediococcus acidilactici),and much lower bitter-tasting components were presented in group HW(Pichia anomala+Staphylococcus xylosus+Staphylococcus carnosus),HS and HV(Pichia anomala+Lactobacillus plantarum).In addition,total levels of biogenic amines detected in all inoculated samples were significantly lower compared with control,especially the content of tyramine(P<0.05).For the volatile compounds,more esters as well as less undesirable odor substances such as aldehydes,were exhibited in four inoculated groups.

Non-enzymatic browning path analysis of ready-to-eat crayfish(Promcambarus clarkii)tails during thermal treatment and storage

This study was carried out to reveal the browning path of ready-to-eat(RTE)crayfish tails during thermal treatment and storage using path analysis.Maillard reactions,lipid oxidation,and phenol oxidation were evaluated in combination with free radical content and FTIR analysis,and direct path coefficients as well as determination coefficients were obtained based on these parameters,such as the absorbance at 294 nm(A294),5-hydroxymethylfurfural(5-HMF),thiobarbituric acid-reactive substances(TBARS),and total phenols(TP).The result showed that the browning of seasoned RTE crayfish tails was ascribe to the synergistic effect of Maillard reaction and lipid oxidation by the order of determination coefficient.After the crayfish hepatopancreas were removed,the content of A294,5-HMF,TBARS,and TP declined more than 30%,specifically affecting the direct pathway from lipid oxidation to Maillard reaction and alleviating the browning.However,no significant change of color was observed in the group without thirteen-spices,while TBARS and free radical content increased by at least 16.7%.The removal of hepatopancreas and the control of Maillard reaction were deemed to be a good measure for inhibiting the non-enzymatic browning of RTE crayfish tails.

Effects of fatty acid chain length and degree of unsaturation on the surface activities of monoacyl trehaloses

The surface properties of monoacyl trehaloses with different acyl chains were investigated at 30℃,40℃,50℃,and 60℃.Monoacyl trehaloses were enzymatically synthesized and purified with silica gel column chromatography and semi-preparative high-performance liquid chromatography(HPLC),and the purity of products was identified by mass spectrometry(MS)and nuclear magnetic resonance(NMR).The surface tension of monoacyl trehalose in pure water was measured using Doüy ring method at different temperatures.The critical micelle concentrations(CMC),surface tension at the CMC,γCMC,and residual area per molecule,a,were estimated from the curves.The CMC value of unsaturated monoacyl trehalose was affected by both the degree of unsaturation and the acyl chain length,and the effect of chain length on the CMC value was much stronger than that of the unsaturation degree.However,there was no significant dependency of theγCMC value and a values on the chain length or the unsaturated degree.

The impact of pH and acid-activated proteases on the decrease of immunological properties of parvalbumin from freshwater fish

Fermentation has been found as an effective method to decrease the hypersensitive reactions of consumers by freshwater fish,but the reason is not clear.Therefore,the aim of this study was to investigate the impact of pH and acid-activated proteases on the decrease of immunological properties of parvalbumin from freshwater fish,by the indicators of SDS-polyacrylamide gel electrophoresis,western blotting,enzyme-linked immunosorbent assay,surface hydrophobicity and circular dichroism.The results showed that black carp(Mylopharyngodon piceus)had the highest level of immunological properties reflected by quantitation,the content of linear epitopes and conformational epitopes of parvalbumin,and IgE-binding rate.Afterwards,purified parvalbumin from black carp was obtained with purity higher than 95%.Then,for acidification and enzyme models,it indicated that acid-activated proteases were the reason for the decrease of immunological properties.Ulteriorly,the mechanism on the level of protein structure was provided,which showed the decrease ofα-helix and the increase ofβ-turn and random coil,as well as the decrease of surface hydrophobicity had joint contribution for the breaking of conformational epitopes.This study could provide a novel guidance for the decrease of immunological properties of fish and promote fish processing industry further.

Co-inoculation of Lactiplantibacillus pentosus 1 and Saccharomyces cerevisiae 31 for a salt-free fish sauce production from channel catfish (Ietalurus punetaus) bone

The study aimed to evaluate the co-inoculation of non-fish sauce strains for a fish sauce production made from Ietalurus punetaus fish bone hydrolysate (FBH) without salt addition. Individual inoculation (Lactiplantibacillus pentosus 1, LP and Saccharomyces cerevisiae 31, SC), and co-inoculation of both strains (FS) were employed, including an uninoculated control. Both strains exhibited good growth in FBH without salt addition. Compared with individual inoculation and uninoculated control, co-inoculation (FS) produced acid and amino nitrogen more quickly, as well as displaying higher sugar consumption. No significant difference was observed in trichloroacetic acid (TCA)-soluble peptides among all groups (P > 0.05). Moreover, significantly lower levels of six bitter amino acids were observed after co-fermentation (P < 0.05). In addition, more alcohols, esters and acids with pleasant notes and fewer unsaturated aldehydes with fishy note were generated after co-inoculation, in the absence of traditional fish sauce off-odor notes. The study demonstrated that the co-inoculation of non-fish sauce strains were appropriate for producing a salt-free fish sauce with better flavor.

Profound changes of mitochondria during postmortem condition used as freshness indicator in grass carp(Ctenopharyngodon idella)muscle

Flesh quality changes during postmortem condition are involved with apoptosis initiation.Therefore,flesh quality evaluation based on the alteration of apoptosis process is quite important.Mitochondria,the regulation place of apoptosis,undergo profound changes in fish muscle during postmortem.Thus,this study aimed to investigate whether mitochondrial related parameters during apoptosis process constitutes a putative early fish freshness marker.Mitochondrial profound impairments during postmortem at 4◦C for 5 days demonstrated that the structural changes[double layer membranes and cristae,volume,swelling,membrane potential(ΔΨm),MPTP opening and membrane fluidity]and dysfunctional changes[energy deficiency and disharmony of Ca2+homeostasis]were occurred during postmortem alteration for energy deficiency and the oxidation by ROS accumulation.Study also investigated energy metabolism related products,TVB-N,lipid and protein oxidation.Compared with the insignificantly increased traditional freshness indicators(except K value)at the initial stage(day 1),the most sensitive parameters based on mitochondrial impairment were[mitochondrial swelling,depolarization ofΔΨm,and membrane fluidity].Therefore,these above parameters might be considered as suitable and early indicators for freshness evaluation.