Differences in textural properties of cooked caponized and broiler chicken breast meat

This study was aimed at evaluating textural properties of cooked chicken breast meats obtained from 3 production systems (conventional raising, feed modification, and caponization) and determining the relationship between instrumental parameters and sensory attributes associated with the texture of capon meat. Texture of cooked breast meats was determined using 3 instrumental methods: Warner-Bratzler Shear (WBS), texture profile analysis (TPA), and uniaxial compression (UC), and sensory analysis by trained panelists. The results indicated that cooked caponized meat showed the lowest values of WBS force, shear energy, hardness, Young's modulus of UC, and the 2 sensory attributes (firmness and number of chews) (P < 0.05). In contrast, springiness and juiciness were the highest in the caponized meat (P < 0.05), suggesting that capon meat was more tender and juicier than the others. Feed-modified chicken samples showed intermediate textural characteristics between the samples of capon and conventionally raised broiler. Pearson's correlation revealed that WBS force, shear energy, Young's modulus of UC, gumminess, and springiness were strongly correlated with 3 sensory attributes (firmness, number of chews, and juiciness). Partial least squares regression (PLSR) demonstrated that 72% of all sensory attributes for the first 2 PLSR components were explained by 36% of the instrumental parameters and the production systems. Loading and score plot illustrated that conventional raising contributed to a high degree of firmness and number of chews, and positively correlated with shear energy, WBS force, gumminess, hardness, and Young's modulus. Contrarily, caponization was negatively correlated with those sensory attributes. The univariate analysis indicated that firmness and number of chews were positively correlated with all instrumental parameters, except springiness. Juiciness was positively correlated with springiness but negatively correlated with the others. The study suggested that the cooked meat of capons could be differentiated from those of broilers raised conventionally and with feed-modified diets based on textural properties. Based on the optimized simulating equation, texture of caponized breast could be explained by WBS force, shear energy, Young's modulus, and gumminess

Effect of Protein Additives on Gelling Properties of Pacific White Shrimp (Litopenaeus vannamei) Meat 65

Abstract: In this study, the effects of egg white (EW), whey protein concentrate (WPC) and bovine plasma protein (BPP) at various concentrations (0 -3%) on properties of Pacific white shrimp gels were elucidated. For one-step heating (90 o C/20 min) and two-step heating (40 o C/30 min followed by 90 o C/20 min), all protein additives showed inhibitory activity toward autolysis of Pacific white shrimp gels. The inhibition was more pronounced in one-step heated gel when the level of protein additive increased which was reflected in the greater extent of myosin heavy chain (MHC) retained. The addition of 0.5% BPP exhibited the most gel enhancing effect as indicated by the highest increase in breaking force of 211.9% and 283.3% for one-step and twostep heated gels, respectively. The addition of BPP resulted in a decrease in L*-value of two-step heated gel and an increase in b*-value. Conversely, EW increased the L*-value, particularly at higher levels of addition