THE RELATIONSHIP BETWEEN COLOR AND WATER-HOLDING CAPACITY IN POSTRIGOR PORCINE LONGISSIMUS MUSCLE

A total 264 pork loins were selected to represent a wide range of pork quality of the longissimus thoracis et lumborum. CIE L*C*h color space showed a closer relationship to the subjective color score than L*a*b*color space. Lightness (L*) was the best measure to predict water-holding capacity (WHC). There were highly significant (p < 0.001) correlations between the measures of color and WHC, and curvilinear relationships between either WHC and color or pHu were observed. In normal muscle color range (reddish-pink), there was considerable variation in WHC. Within the RSE + RFN groups of muscles, less variation of WHC could be accounted for by variations in color measurements. Color and WHC were not closely related and suggest that the RSE (reddish-pink, soft, exudative) condition should be classified as a separate quality category of pork muscle.     

Effect of soluble soybean protein hydrolysate-calcium complexes on calcium uptake by Caco-2 cells

Soybean protein hydrolysates (SPHs) bind with calcium, forming soluble SPH-calcium complexes via the carboxyl groups of glutamic and aspartic acid residues. However, their effect on calcium uptake is still unclear. In this study, Caco-2 cells were used to estimate the effect of SPH-calcium complexes with different molecular weights on calcium uptake in vitro. The changes in intracellular calcium ion concentration were measured by Fura-2 loading and expressed in fluorescence intensity. SPH-calcium complexes could promote calcium uptake. Improved fluorescence intensity was significantly different in SPH-calcium complexes (10 to 30 kDa), SPH-calcium complexes (3 to 10 kDa), and SPH-calcium complexes (1 to 3 kDa). The maximum levels of relative fluorescence intensity (18.3) occurred with SPH-calcium complexes (10 to 30 kDa). The effect of SPH-calcium complexes (10 to 30 kDa) on Ca(2+) increase was determined to be concentration dependent in the range of 0.5 to 4 mg/mL. Our results indicate that soybean protein itself might be responsible for promoting calcium absorption.     

A study of the soluble complexes formed during calcium binding by soybean protein hydrolysates

ABSTRACT:  The soluble complexes formed between hydrolyzed soybean protein and calcium at pH 7.4 were investigated using dialysis, gel chromatography, and Fourier transform infrared spectrometry (FTIR). The results demonstrate that the amount of calcium bound was significantly different for soybean protein hydrolysates obtained using the proteases neutrase, flavourzyme, protease M, and pepsin. Maximum levels of calcium binding (66.9 mg/g) occurred with hydrolysates produced using protease M. Peptide fragments exhibiting high calcium binding capacity had molecular weights of either 14.4 kDa or 8 to 9 kDa, and the calcium binding capacity was linearly correlated with carboxyl group content ( R ²= 0.8204). FTIR experiments revealed that upon binding calcium, the amide I band underwent a shift to lower wave numbers. A wide, intense Ca–O absorption band also appeared between 400 and 100 cm⁻¹ in the far-infrared spectrum. The width and intensity of this band increased after treatment of samples with glutaminase. The amount of bound calcium was related to both the molecular weight of the peptides and to the carboxyl group content, and the most likely sites for calcium binding are the carboxyl groups of Asp and Glu.     

Effect of Lactic Acid Bacterial Fermentation on the Characteristics of Minced Mackerel

ABSTRACT: To improve the functionality and quality of seafood, mackerel minces were fermented with lactic acid bacteria (LAB) ∼ Lactobacillus plantarum CCRC10069, Lactococcus lactis subsp. lactis CCRC 12315, Lactobacillus helveticus CCRC 14092, or their combination at 37 °C. Rapid growth of LAB, decline in pH, suppress of main microflora, increases in whiteness, Hunter L, nonproteinous nitrogen, sensory quality, and free amino acids related to taste were observed. However, VBN of samples fermented with LAB were still d ≤ 25 mg/100g after 36 h fermentation. SDS-PAGE indicated the obvious degradation of water- and salt-soluble muscle proteins after 12 h fermentation. Animal test demonstrated the LAB-fermented mince has the functionality on reduction of blood pressure, glucose, and total cholesterol of SHR.     

Synergistic antiyeast activity of garlic oil and allyl alcohol derived from alliin in garlic

ABSTRACT:  Garlic oil (GO) and allyl alcohol (AA), both derived from alliin in garlic using different preparation methods, cause potent growth inhibition in yeasts. GO and AA inhibited Candida utilis ATCC42416 in different ways: GO has fungistatic activity while AA has fungicidal activity. GO and AA have almost identical antimicrobial potencies against the indicator yeast, with minimum inhibitory concentrations of about 25 ppm when tested individually. When GO and AA were tested in combination, the antimicrobial efficacy significantly increased. Combinations of AA and GO at 1 and 9 ppm, 2 and 7 ppm, 5 and 5 ppm, and 6 and 3 ppm, respectively, inhibited C. utilis completely. The sum of the fractional inhibitory concentrations (FICs) in the 2-component (GO and AA) combination was as low as 0.37 for C. utilis , indicating strong synergism. The sum of the FICs of diallyl disulfide and diallyl trisulfide in combination with AA was larger than that of the GO–AA combination, suggesting that the synergy was lower.