Effects of Different Rearing Modes on the Muscular Histological Traits and Meat Tenderness of Chicken

[ Objective] The aim of this experiment was to explore the effects of different rearing modes on muscle histological traits and muscle ten demess and to provide theoretical basis for regulating chicken meat quality. [ Method] The effects of outdoor rearing, indoor rearing and cage rea ring modes on the muscular histological traits and meat tenderness of Hetian chicken at the age of 8 weeks, 12 weeks and 16 weeks were re searched. [Result] The results showed that the breast and thigh muscle fibre diameter and muscle shear force of outdoor rearing chicken were sig nificently higher than that of cage rearing chicken （ P 〈 0.05）, and muscle fibre density was significantly lower than that of cage rearing chicken （ P 〈 0.05）. With aging, the muscle fibre diameter and shear force increased and muscle fibre density decreased （ P 〈 0.05）. The muscle fibre di ameter and shear force of male were higher than that of female. The correlation analysis showed that the breast muscle shear force had a signifi cantly positive relation with fibre diameter and negative relation with fibre density （ P 〈 0.05）, but thigh muscle shear force had an insignificantly pos itive relation with fibre diameter and fibre density. [ Condusion] Muscular histological traits varied in different rearing modes, and the outdoor rearing promoted the muscular fibre development and increased the muscular shear force.

Muscular Histological Traits and Meat Tenderness of Different Local Broilers

Objective＇ To study the muscular histological traits and their relationship with meat tenderness in local broilers and provide a theoretical basis for promoting meat quality of broiler. [Methed] The diameter and density of muscle fiber of three local varieties of chicken （Beijing Fatty broil- er, Fujian Hetian broiler and Taining Black broiler） were detected at the age of 8 weeks, 12 weeks and 16 weeks. And the differences in the diame- ter and density of muscle fiber as well as their relationship with meat tenderness were respectively analyzed with SAS software. [ Resultl Fatty broil- er had the smallest muscle fiber diameter while Hetian broiler the largest; Fatty broiler had the highest muscle fiber density while Hetian broiler the lowest Hetian broiler had the highest muscle shear force of leg muscle while Black broiler the lowest （ P 〈0.05） ; Black broiler had the highest mus- cle shear force of breast muscle while Fatty broiler the lowest （P〈0.05）. The correlation analysis showed that the shear force of breast muscle and leg muscle had significantly positive relation with fiber diameter and significantly negative relation with fiber density （ P 〈 0.05）. [ Conclusion] Muscu- lar histological traits varied in different local broilers, and the muscular shear force had significantly relation with fiber diameter and density.

Effect of Disinfection Time on Microbial Content and Quality of Cold Fresh Chicken

[Objective] The aim was to provide reference for the production technolo- gy of cold fresh chicken. [Method] Lactic acid was used as the disinfectant in cooling water, so as to study the effect of disinfection time on the microbial content and quality of cold fresh chicken. [Result] With disinfection of 20 min, the removal rates of the total colonies, coliforms and moulds reached over 95%. As the disinfec- tion time was further extended, it had no significant effect on the removal effects of the microbial content and could affect the tenderness and color of cold fresh chick- en. [Cendusion] The study provides references for the design and optimization of the production process of cold fresh chicken.

Single Nucleotide Polymorphism Genotyping of Calpastatin Gene Using the ARMS Compared with the RFLP

Calpastatin is an endogenous inhibitor of calpain which is responsible for the breakdown of myofibrillar proteins, The association of Single Nucleotide Polymorphism （SNP） in the calpastatin gene with meat tenderness is an important topic in meat production. Therefore efficient procedure to investigate the SNP is necessary. The objectives of this study were to detect the SNP of calpastatin gene at domain L marker （G/C transversion） of the Kamphaengsaen beef breed （KPS cattle; n = 26） by the Amplification Refractory Mutation System （ARMS） compared with the Restriction Fragment Length Polymorphism （RFLP） methods and to determine the genotypes of the KPS cattle at that marker. Genomic DNA of calpastatin gene extracted from blood of the KPS cattle was detected with ARMS and RFLP methods. The ARMS system has utilized two primer pairs to amplify the two different alleles of a polymorphism in single PCR reaction to detected single base mutation. In this method, the alleles-specific primers had a mismatch at 3＇ terminal base and a second deliberate mismatch at position -2 from 3＇ terminus. While the RFLP method detected a polymorphism using PCR-base technique follow by RsaI restriction enzyme. Amplification of the ARMS method revealed that the results were not different from the conventional method of RFLP. Analysis of genotypes revealed that the KPS cattle inherited the CC, CG and GG genotypes at domain L marker. These were reliable when verified by nucleotide sequence analysis of PCR products. The animals were genotyped and determined for tenderness phenotype with this marker that predicted variation of an intronic polymorphism at domain L of the calpastatin gene. Therefore, the ARMS method was simple, efficient technique, and suitable for detecting SNP at domain L marker of the calpastatin gene.

Industrial High Pressure Processing of Foods： Review of Evolution and Emerging Trends

High Pressure Processing （HPP）, in the range of 200 MPa to 600 MPa/29,000 psi to 87,000 psi, is the most advanced emerging non-thermal processing technology for food. The constant improvements of high pressure equipment concerning productivity and production costs have facilitated the increase of industrial uses of the technology. This paper reviews some of these advances in high pressure food processing including development of new functional beverages the new value proposals being offered by copackers substitution of traditional thermal techniques for novel product manufacturing and refrigerated services suppliers. Substitution of thermal treatments for meat processing and tenderisation of low value meat cuts.