This study investigated the effects of different types(KCl,NaCl,and CaCl2)and concentrations(five ionic strengths)of salt on the gel properties of surimi.The results indicate that KCl and NaCl were more effective than CaCl2 in improving the gel properties of surimi.As the KCl,NaCl,and CaCl2 concentrations increased,the gel strength,water-holding capacity,and textural properties of surimi increased but declined when the CaCl2 concentration exceeded 1.89%.The KCl,NaCl,and CaCl2 concentrations that resulted in maximum storage modulus were 2.55%,5%,and 1.89%,respectively.K+and Na+promoted the conformational transition of surimi proteins from α-helix to β-sheet,while Ca2+tended to convert α-helix into random coil and β-turn structures.Meanwhile,among all NaCl concentrations tested,3%NaCl resulted in the highest content of ionic bonds in surimi gels.The contents of both hydrogen bonds and ionic bonds increased with KCl concentration up to 5.09%and CaCl2 concentration up to 1.27%and then declined.Additionally,addition of KCl or NaCl resulted in higher levels of hydrophobic interaction and a higher relative content of immobilized water than did CaCl2 addition,indicating increased water-holding capacity of surimi gels.This study provides a reference for improving the gel properties of surimi and exploring salt substitute formulations in the food industry.
Using metabolomics,this study explored the relationship between the quality deterioration and the metabolic changes in refrigerated large yellow croaker(Larimichthys crocea)during refrigeration.Key differential metabolites associated with quality deterioration across fish samples after 0,9,and 18 days of refrigeration were identified by gas chromatography-quadrupole-time-of-flight mass spectrometry,and the metabolic pathways in which the differential metabolites may be involved were analyzed.The results showed that as refrigeration time increased,the types and contents of metabolites such as amino acids,carbohydrates,and nucleotides significantly changed in large yellow croaker muscle.The differential metabolites were primarily concentrated in amino acid metabolism pathways,such as arginine and proline metabolism;glycine,serine,and threonine metabolism;and cysteine and methionine metabolism.Proline,glutamate,isoleucine,glycine,methionine,tyrosine,valine,guanosine,uracil,ribose,thymidine,xanthine,and 5'-inosine monophosphate were identified as key differential metabolites.The degradation of amino acids and the generation of biogenic amines were closely related to the decline in the freshness and shelf life of large yellow croaker,while the degradation of nucleotide substances was related to the decrease in the taste.
The purpose of this study was to explore the feasibility of using pretreated cattle skin as an ingredient in minced meat products.The effects of soaking temperature,sodium carbonate concentration,amount of iced water used during cow skin disruption,and amount of cow skin to beef on the texture characteristics,color,sensory score,yield of beef meatballs and pH of meat mince were investigated by one-at-a-time method.Furthermore,these parameters were optimized by response surface methodology.The results showed that the amounts of iced water and cow skin used significantly affected the sensory score and yield of beef meatballs(P<0.05).The highest sensory score(82.9)and yield(120.5%)were obtained when 10%(m/m)sodium carbonate was added during cattle skin pretreatment,219%(m/m)iced water was added during cow skin disruption,and 13%pretreated cattle skin was added to minced beef.The results of this study provide a theoretical basis for further research on the effect of cow skin on the quality of beef meatballs.
To investigate the effect of wet aging time on the flavor of cooked pork,the flavor and taste substances of cooked pork longissimus dorsi with different wet aging times(1,12 h,1,3,5,7,and 10 d)were measured.The results showed that a total of 38 volatile flavor compounds were identified,and the total content of volatile flavor compounds showed a trend of initially increasing and then decreasing.Aldehydes were the most abundant volatile compounds,and the highest content of aldehydes of 2 163.50 μg/kg was observed after one day of aging.Hexanal,heptanal,octanal,nonanal,and 1-octen-3-ol were key aroma compounds.The contents of flavor nucleotides and umami amino acids in cooked pork initially increased and then decreased,with inosinic acid and equivalent umami concentration reaching the highest values of 172.12 and 8.35 mg/100 g after one day of aging,respectively.The contents of sweet and bitter acids were the highest at 12 h of aging.Therefore,cooked pork after wet aging for one day had the best flavor.
In this study,the effects of protein oxidation and NaCl concentration on the structure of yak myofibril protein(MP)were investigated.To this end,MP was oxidized for 1 h in a Fenton oxidation system and treated for 1 h with different NaCl concentrations under three pH values(5.0,6.0 and 8.0),respectively.The total sulfhydryl content,surface hydrophobicity,solubility,sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)pattern,and microstructure of treated MP were determined.The results showed that at a fixed pH,the total sulfhydryl content and solubility decreased with increasing H2O2 concentration,and the surface hydrophobicity increased.In addition,the degree of expansion declined horizontally.At a fixed H2O2 concentration,the total sulfhydryl content and solubility increased with increasing pH,and the surface hydrophobicity decreased,accompanied by lateral expansion,narrowing of the A-band and destruction of the Z-line.At a fixed pH,the solubility increased with increasing NaCl concentration,and the surface hydrophobicity decreased,accompanied by lateral expansion and destruction of the transverse bridge.At a fixed NaCl concentration,the solubility increased with increasing pH,the surface hydrophobicity decreased,and lateral expansion occurred.At pH 8.0 and 1 mol/L NaCl concentration,both the M-line and Z-line were obviously destroyed,the structure of MP became blurred,the myotome was broken,the transverse bridge was destroyed,and coarse filaments were separated from fine ones.In conclusion,both protein oxidation and NaCl had adverse effects on yak MP under different pH conditions,and protein oxidation had the lowest negative impact on MP structure at pH 6.0 and a NaCl concentration of 0.4 mol/L.
