Physical evaluation of popped cereal snacks with spent hen meat

Various blends of spent hen meat and grains (potato starch, corn starch, and rice flour) were popped using a popping machine. Lowest bulk density was observed in the snack with 1:2 ratio of meat and potato starch. Except for the popped snack with meat and rice flour, as the starch content increased, bulk density decreased gradually. Popped snacks with grains only were higher in L* value than those with meat and grains. The a* and b* values increased with increasing meat content. All popped snacks were significantly different (P<0.001) in bulk density, color, and breaking force. As the grain content of snacks increased, the size of the air cells also increased. Results of scanning electron microscopic and optical microscopic observations revealed the popping degree of snack with starch and spent hen meat was affected by the presence of meat. The optimum ratios of meat to grain for high expansion ratio were determined to be 1:2 and 1:3 of meat to corn starch and potato starch.     

Myofibrillar protein extracts from spent hen meat to improve whole muscle processed meats

Myofibrillar protein (MP) from spent hen meat was used as an ingredient for chicken breasts and pork hams. Cooking loss (CL) and texture of both products were evaluated. Salt-soluble MP was extracted following centrifugation. A brine with 6% MP or a brine without MP were injected into meat to 20% of the original meat weight. CL was reduced in pork hams treated with 6% MP (P<0.05). Chicken breasts with 6% MP had greater hardness and gumminess than those without MP (P<0.05). Pork hams with 6% MP had greater hardness, gumminess and chewiness than those without MP (P<0.05). It was concluded MP from spent hen meat may be used to improve the functional properties of whole-muscle meat products.     

Moisture sorption properties of chitosan

The moisture equilibrium isotherms of chitosan were determined at 20, 30, 40, 50 and 60 °C, using the gravimetric static method. Experimental data were analyzed by the GAB, Oswin, Halsey and Smith equations. Isosteric heat and differential entropy of sorption were determined from the GAB model using the Clausius-Clapeyron and Gibbs-Helmholtz equations, and pore size distribution was calculated by the Kelvin and Halsey equations. The GAB and Oswin equations showed best fit to the experimental data with R² ≈ 99% and low mean relative deviation values (E% < 10%). Monolayer moisture content values (from 0.12 to 0.20 kg kg⁻¹) and water surface area values (from 450 to 700 m² g⁻¹) decrease with increasing temperature. Isosteric heat and differential entropy of sorption were estimated as a function of moisture content. The Kelvin and Halsey equations were adequate for calculation of pore size distribution, which varied from 0.5 to 30 nm.     

Investigation of the peptides with calcium chelating capacity in hydrolysate derived from spent hen meat

Calcium peptide chelates are developed as efficient supplements for preventing calcium deficiency. Spent hen meat (SHM) contains a high percentage of proteins but is generally wasted due to the disadvantages such as hard texture. We chose the underutilized SHM to produce peptides to bind calcium by proteolysis and aimed to investigate chelation between calcium and peptides in hydrolysate for a sustainable purpose. The optimized proteolysis conditions calculated from the result of response surface methodology for two-step hydrolysis were 0.30% (w_enzyme/w_meat) for papain with a hydrolysis time of 3.5 h and 0.18% (w_enzyme/w_meat) for flavourzyme with a hydrolysis time of 2.8 h. The enzymatic hydrolysate (EH) showed a binding capacity of 63.8 ± 1.8 mg calcium/g protein. Ethanol separation for EH improved the capacity up to a higher value of 68.6 ± 0.6 mg calcium/g protein with a high association constant of 420 M⁻¹ (25°C) indicating high stability. The separated fraction with a higher amount of Glu, Asp, Lys, and Arg had higher calcium-binding capacity, which was related to the number of ─COOH and ─NH₂ groups in peptide side chains according to the result from amino acid analysis and Fourier transform infrared spectroscopy. Two-step enzymatic hydrolysis and ethanol separation were an efficient combination to produce peptide mixtures derived from SHM with high calcium-binding capacity. The high percentage of hydrophilic amino acids in the separated fraction was concluded to increase calcium-binding capacity. This work provides foundations for increasing spent hen utilization and developing calcium peptide chelates based on underutilized meat.     

Quality characteristics of imitation crab sticks made from Alaska Pollack and spent laying hen meat

Imitation crab stick (ICS) samples were divided into four treatments, a control (C) prepared with Alaska Pollack as a commercial ICS, T1, which consisted of Alaska Pollack with spent laying hen surimi collected by the pH adjust method, T2, which was composed of Alaska Pollack with spent laying hen surimi collected by the filter cake method, and T3, which consisted of Alaska Pollack with whole spent laying hen meat batter collected by the cutting method. The moisture content was significantly higher in T3 than in the other ICS samples; but, there was no significant difference in the crude protein, fat and ash content, regardless of the spent laying hen substitution methods. The lightness (L∗) and whiteness (W) was higher in the control than in the other ICS samples at 0 days of storage, whereas the yellowness (b∗) was significantly higher in T3 than in the other ICS samples. The level of polyunsaturated fatty acids was significantly higher in the control group than in the other ICS samples. Additionally, the pH increased with storage time in the spent laying hen substituted samples (T1, T2 and T3), with T1 showing a significantly higher pH during storage. The TBARS value increased with storage time in all ICS samples, with T2 showing a significantly lower TBARS value than the other ICS samples at the beginning and end of the storage periods. There was no significant difference in any sensory evaluation items among the ICS samples during storage. Thus, we assumed that T3 was better than other ICS samples, because T3 method (cutting) is much easier to collect spent laying hen surimi than T1 (pH adjust) and T2 (filter cake).     

Mechanical and gelling properties of comminuted sausages containing chicken MDM

The present investigation focuses on the physicochemical properties, rheological behaviors and texture of raw and cooked emulsions containing different mechanically deboned meat (MDM) from chicken. MDMs were produced from the neck, backs and thighs. The texture and mechanical profile analyses were performed using a small deformation dynamic oscillation in a shear and instrumental texture analyzer. The mechanical spectra of the raw and cooked MDM emulsion gels were classified as weak gels based on their frequency sweep and tan δ results. Both the G′ and G″ values increased with increasing frequency in the temperature of 4 and 10 °C. The MDM from thighs had the lowest water holding capacity (WHC) and emulsifying (EC) values, while the MDM from backs had significant values of 2.41 and 128.87, respectively. The cooked emulsion containing backs showed the highest hardness and cohesiveness values, while the emulsion containing necks and thighs had the lowest texture parameters.     

Moisture sorption isotherms and thermodynamic properties of walnut kernels

The moisture sorption isotherm data of walnut kernels stored in a chamber, the relative humidity (r.h.) of which is regulated by atomizing humidifier, were determined at three different temperatures (25, 35 and 45 °C) and r.h. ranging from 10% to 90%. Eight models, namely the GAB, BET, Henderson, Iglesias and Chirife, Oswin, Peleg, Smith and Caurie equations, were fitted to the sorption data. Several statistical tests were adopted as the criteria to evaluate the fitting performance of the models. Of the models tested, the Peleg model gave the best fit to experimental data. The surface area of a monolayer was calculated. The BET equation was applied to the monolayer moisture content and the corresponding a_w values at which a monolayer forms are presented. The experimental data were also used to determine the thermodynamic functions such as isosteric heat of sorption, sorption entropy, spreading pressure, net integral enthalpy and entropy. The sorption isosteric heats for walnut kernels were determined by the application of the Clausius-Clapeyron equation to sorption isotherms obtained from the best-fitting equation. Isosteric heats decreased with increase in moisture content and approached the latent heat of pure water. Adsorption entropy increased with increasing moisture content, and then it decreased sharply with increase in moisture content. The spreading pressures (adsorption and desorption) increased with increasing water activity. Net integral enthalpy of adsorption increased slightly with moisture content to a maximum value. Thereafter, it remained constant. Net integral entropy of adsorption was negative in value and it decreased with increase in moisture content to a minimum value, and then increased slightly with increase in moisture content.     

淘汰蛋鸡肉糜功能特性影响因素研究进展

淘汰蛋鸡肉糜加工过程中的漂洗，加热，添加剂应用是影响其功能特性的主要因素。作者介绍了淘汰蛋鸡肉糜的功能特性，并对其主要影响因素－加工工艺和添加剂进行了综述论述。     

Isolation of Yersinia from raw meat (pork and chicken) and precooked meat (porcine tongues and sausages) collected from commercial establishments in Mexico City

A total of 160 meat product samples were collected from commercial outlets in Mexico City to investigate the presence of different species of Yersinia by the 4 degrees C enrichment method after 1, 3, 5, and 7 days of incubation using alkaline treatment and isolating in cefsulodin-Irgasan-novobiocin and MacConkey agars with Tween 80. Overall, Yersinia spp. were isolated from 27% of the samples analyzed, whereas 40% of the raw and only 13% of the precooked samples were contaminated. Although 2,970 colonies showed Yersinia characteristics, only 706 (24%) actually corresponded to this genus: 49% were Yersinia enterocolitica, 25% Yersinia kristensenii, 15% Yersinia intermedia, 9% Yersinia frederiksenii, and 2% Yersinia aldovae; 10% corresponded to biotype 2, 2% to biotype 3, and 4% to biotype 4. The presence of Yersinia in raw and cooked meat products represents a health risk for consumers in Mexico, where further clinical studies are needed to assess the epidemiological importance of this pathogen.     

Quality of comminuted sausages formulated from mechanically deboned poultry meat

Comminuted sausages formulated with mechanically deboned poultry meat-MDPM (turkey or chicken, frame or neck) treated in different ways before production (vacuum packed MDPM or air packed skeletons deboned at production) and stored frozen for 6 or 18 weeks have been studied using a full-factorial design and chemical, physical and sensory analysis. MDPM was obtained from a Beehive separator. Comminuted sausages with MDPM from turkey frames, stored at -25?°C as skeletons, packed in air for 18 weeks developed marked rancid odour and flavour which could also be detected by thiobarbituric acid reactive substances (TBARS) and the concentration of volatile compounds. Vacuum packed mechanically deboned meat irrespective of species and carcass part could be stored for up to 18 weeks and used in formulation of sausages without any serious changes in their sensory profiles. Instrumental colour differences between sausages were mainly due to species. Turkey sausages were darker, redder and less yellow than chicken sausages. Moisture and fat contents were influenced by carcass part and to a lesser extent depended on species and storage time. Principal least squares regression (PLS2) showed close relationships between instrumental parameters and sensory attributes. TBARS, hexanal and volatile compounds were highly correlated with rancid flavour while redness (a(?)) was strongly related to sensory colour hue and colour strength.     

发酵剂对熏马肠脂肪氧化的影响

通过对熏马肠发酵成熟过程中的过氧化值、硫代巴比妥酸值、双烯值、脂肪氧合酶活力(LOX)、超氧化物歧化酶活力(SOD)和过氧化氢酶活力(CAT)等指标的测定,研究发酵剂对熏马肠发酵成熟过程中的脂质氧化、氧化酶和抗氧化酶活力的影响。结果表明:与对照组相比较,发酵剂可以显著抑制脂质氧化和LOX活力,且显著提高SOD和CAT活力。通过相关性分析表明,发酵剂组的LOX活力与过氧化值、硫代巴比妥酸值和双烯值这3个氧化指标呈不显著负相关,相关系数为0.089~0.427。SOD和CAT活力与3个氧化指标呈显著、极显著负相关,相关系数为0.684~0.970。     

发酵剂对熏马肠脂肪酶活力的影响

主要研究发酵剂对熏马肠发酵成熟过程中脂肪酶活力的影响。结果表明,酸性脂肪酶活力、中性脂肪酶活力、磷脂酶活力在发酵成熟过程中持续下降,并且发酵剂组的三种酶活力在添加发酵剂后显著高于空白组(p0.05)。通过相关性分析表明,在熏马肠发酵成熟过程中,发酵剂组中的三种酶活力与p H、水分含量及盐分含量呈极显著相关性(p0.01)。     

微波辅助-固相微萃取联用技术萃取腊肉中多环芳烃的研究

通过比较不同提取方法对多环芳烃(PHAs)的提取效率,建立了腊肉中多环芳烃的微波辅助-固相微萃取联用技术(MAE-SPME)和气相色谱(GC)分析测定方法,优化了16种多环芳烃(PHAs)化合物的分离测定条件,16种PAHs回收率范围为78.80%～101.2%,相对标准偏差为2.5%～6.1%.该方法具有灵敏度高、准确度好、能同时分离测定16种多环芳烃化合物的优点,适合于腊肉中多环芳烃化合物的分析测定.     

鸡胸肉和鸭胸肉凝胶性能的差异

通过分析鸡胸肉和鸭胸肉生肉糜的p H、蛋白质含量、蒸煮得率、流变学特性和凝胶质构,研究鸡胸肉和鸭胸肉凝胶性能之间的差异。发现鸡胸肉和鸭胸肉生肉糜蛋白质含量分别为17.86%和14.69%,p H值为6.33和6.21,说明鸡胸肉生肉糜有较高的蛋白质含量和p H值。蒸煮后,鸡胸肉肉糜有较高的L*值、蒸煮得率、硬度、弹性和内聚性,而鸭胸肉肉糜的a*值较高。流变结果表明,鸭胸肉蛋白对温度变化敏感,而在20~80℃,鸡胸肉肉糜的存储模量(G')高于鸭胸肉肉糜。     

Moisture sorption isotherms and thermodynamic properties of apple Fuji and garlic

The moisture equilibrium isotherms of garlic and apple were determined at 50, 60 and 70 °C using the gravimetric static method. The experimental data were analysed using GAB, BET, Henderson–Thompson and Oswin equations. The isosteric heat and the differential entropy of desorption were determined by applying Clausius–Clapeyron and Gibbs–Helmholtz equations, respectively. The GAB equation showed the best fitting to the experimental data (R² > 99% and E% < 10%). The monolayer moisture content values for apple were higher than those for garlic at the studied temperatures; the values varied from 0.050 to 0.056 and from 0.107 to 0.168 for garlic and apple, respectively. The isosteric heat and the differential entropy of desorption were estimated in function of the moisture content. The values of these thermodynamic properties were higher for apple (in range 48–100 kJ mol^?1 and 14–150 J mol^?1 K^?1) than for garlic (in range 43–68 kJ mol^?1 and 0–66 J mol^?1 K^?1). The water surface area values decreased with increasing temperature. The Kelvin and the Halsey equations were used to calculate the pore size distribution.