【Objective】 The objective of this experiment is to study the pyridinoline cross-links of collagen and dissect its relevance to the shear force of beef.【Method】 Samples were divided into two groups.The first group consists of the same marbling with different ages.The second consists of the same age with different marblings.The shear force of beef,solubility and hydroxylysylpyridinium,lysylpyridinium of collagen were measured.【Result】According to the results of the first group,as bull aged,HP cross-links increased,LP cross-links increased firstly,and then decreased,which was followed by the decreasing of collagen solubility and the increasing of shear force.According to the results of the second group,as fattening,HP cross-links decreased,the solubility of collagen increased,and the shear force of beef decreased.【Conclusion】In the fattening,the synthesization of HP cross-link was restrained.There are shorts of mature cross-links in collagen,resulting in transition of gelatin more easily.So beef turns tenderer.

In this paper,the pH,protein solubility,dynamic viscoelasticity and gel properties(water-holding capacity(WHC),gel strength and gel elasticity) of fresh,chilled and frozen porcine longissimus muscle were conducted comparative comparison.The results showed that pH and protein solubility of fresh meat were the highest,and the gel properties and dynamic viscoelasticities were better.The pH and protein solubility of chilled meat were relatively low,and their gel properties and dynamic viscoelasticity were inferior to those of fresh meat.The pH,protein solubility,WHC and dynamic viscoelasticity of frozen meat were the lowest,however,the gel strength and gel elasticity of frozen meat were lower than those of fresh meat and higher than those of chilled meat.Therefore,refrigeration process can damage the functional properties of meat,and functional quality of fresh meat was the best.

A large quantity of fumes may be generated as a result of frying during the production of roast chicken.PM2.5 and formaldehyde concentration in the fumes and the contents of the hazardous substances 3,4-benzypyrene and heterocyclic amines in the PM2.5 particles were determined.The maximum levels of PM2.5 and formaldehyde were detected to be 2440 μg/m3 and 0.270 mg/m3,which exhibited a 31.5-fold increase compared with China’s limit level 2 for air quality(75 μg/m3) and a 2.86-fold decrease compared with China’s atmospheric emission limit,respestively.The PM2.5 particles were detected to contain 18.35–30.68 μg/g 3,4-benzypyrene and 14.87–37.72 μg/g.

This study was focused on a comparative evaluation of the sensory quality properties and processing characteristics of striploin and knuckle meats from Yanbian and Nanyang yellow cattles. Results showed that the a * value of Yanbian beef was significantly higher than that of Nanyang beef( P < 0.05), but the L * and b * values were significantly lower than those of Nanyang beef( P < 0.05). The juiciness of striploin from Yanbian cattle was better than that of Nanyang beef, while the juiciness of knuckle was worse than that of Nanyang beef. The cooking loss showed that Yanbian beef had a higher yield during processing than Nanyang beef. The striploin of Yanbian cattle had better tenderness with shear force of 3.19 kg/cm 2, which was suitable for frying and roasting. The gel p roperty of Yanbian beef was better than that of Nanyang beef, so Yanbian beef was suitable for preparing gel-type products. Nanyang beef had a better emulsifying property, and thuswas suitable for preparing emulsification-type products.

To establish a formaldehyde detection method, including a method of extraction, in traditional smoked meat products, steam distillation was chosen as the preparation method. The effects of distillation time, 10% phosphoric acid solutions dosage, soaking time and water coolant flow rate on the extraction amount of formaldehyde were investigated. An orthogonal design L9 (34) was applied to optimize the extraction conditions. The following optimum extraction conditions were determined: distillation time of 50min, 10% phosphoric acid solution dosage of 3mL, soaking time of 2h and water coolant flow rate of 2.2×10−5m3/s. The recoveries of standard additions of formaldehyde (10, 20, and 30mg/kg) were found to be 85.79%, 91.64% and 83.45%, respectively. The repeatability relative standard deviation (RSD) was 2.669%, and the reproducibility RSD was 6.536%. The detection limit was 0.4602mg/kg with the proposed method in smoked meat products. The smoked meat products contained high formaldehyde concentrations (up to 125mg/kg wet weight) when the proposed method was used.

The distribution regularity and microstructure of fat particle in meat batters were investigated.Porcine longissimus muscle was used as raw material.After grinding and chopping for 3 min,the mash was chopped with pork fat for 5 min.Light microscope and electron microscope were used to observe the meat batter and the gel.The results showed that the fat was shearing into liquid fat droplets and solid fat granules of different sizes and shapes,some fat droplets and fat granules could even be aggregated into fat particle clusters.They were all covered with a layer of protein film and dispersing in the protein matrix individually or by a coalescent way.

Polyphosphates have been extensively used as food additives in meat processing,however,the addition of excess polyphosphates in exported aquatic products from China has often happened in recent years.Ion chromatography method applied to the determination of polyphosphates in meat possesses the advantages of low limit of detection,high sensitivity and reproducibility,good anti-jamming ability and accurate results.This paper introduces recent research achievements on ion chromatographic determination of polyphosphates in meat and compares ion chromatography method and several other common methods,which will have some practical significance to control the addition of polyphosphates and ensure meat safety.

Smoked meat products are very popular worldwide.The traditional smoking technology has defects,easily leading to the pollution of polycyclic aromatic hydrocarbons(PAHs) and formaldehyde.This paper outlines some defects of the traditional smoking technology and put forward the solutions: inhibiting the formation of PAHs and using liquid smoking.The first solution has limitation and can not solve the problem of formaldehyde pollution.However,the second not only retains the flavor of traditional smoked meat products,but also yields safe and healthy products,thus being worth advocating and popularizing.