奶公犊牛肉营养成分的分析

检测分析奶公犊牛肉的基本营养成分,奶公犊牛肉中蛋白质、粗脂肪、水分、灰分、碳水化合物含量和能量分别达到23.76%、1.38%、77.66%、1.35%、0.85%和469.43 k J/100 g;奶公犊牛肉含有丰富的微量元素,其中奶公犊牛肉中铁元素和铜元素为成年黄牛肉的10倍之高;奶公犊牛肉中总氨基酸含量略低于成年黄牛肉,风味氨基酸占总氨基酸的比例高于成年黄牛肉。     

Evaluation of pork colour sensory colour assessment using trained and untrained sensory panellists

M. longissimus dorsi and M. psoas major minced pork patties from three dietary treatment groups of DLY (Duroc/Landrace/Yorkshire) cross bred pigs were packaged in polythene bags and placed in a retail refrigerated display cabinet at 5±1?°C, under fluorescent light (1000 lux) for up to 5 days. Each dietary treatment group consisted of pigs (n=7) fed either a low vitamin E diet (80 mg dl-α-tocopheryl acetate/kg of feed), supplemental iron [7 g iron (II) sulphate/kg feed] or supplemental vitamin E (200mg dl-α-tocopheryl acetate/kg of feed)+supplemental iron. Samples were subjected to visual colour evaluation by a trained sensory panel (n=8) and an untrained panel (n=8) on days 0, 1, 3 and 5 of display. The signal to noise (S/N) ratios for assessors and replicates for the trained assessor group were higher than those of the untrained assessor group indicating greater reliability in the trained assessor results. The trained assessor group produced relatively normal percentile distributions for sensory terms in the assessment of both M. longissimus dorsi and M. psoas major muscles. The untrained assessor group displayed more skewed or non-symmetric distributions for M. longissimus dorsi, but produced a normal distribution for M. psoas major. Quantitative and qualitative analysis of the sensory profiling by both the trained and untrained groups of test subjects showed that in general sensory training contributed to a more effective visual sensory evaluation of M. longissimus dorsi in terms of metmyoglobin development. However, this is not the case for M. psoas major where both groups of assessors produced comparable results. Use of uniploar scaling did not improve the discriminative ability of assessors, both trained and untrained, in assessment of blue and yellow. The untrained group of assessors were even less effective in the use of these scales. It appeared that the sensory visual assessment of meat products can be performed effectively without training when the product colour is familiar to the assessors. However, training of panellists becomes relevant when a more unfamiliar product of unfamiliar colour is to be assessed and the unintuitive aspect of discrimination may play a greater role in the objective sensory colour assessment of meat.     

Nutritional Value of Veal Bone Hydrolysate

Industrial veal hydrolysate was produced enzymatically for possible use as a gelatin-replacing ingredient for human consumption. Protein digestibility and nutritional value were determined in vitro and in vivo. Net protein ratio (= 2.65) and true digestibility (= 80.3) were compared with gelatin and caseinate. Protein digestibility was determined by pH-stat method and cell dialysis. Amino acid composition including 4-hydroxyproline, allowed determination of connective tissue, amino acid score and protein digestibility corrected amino acid score. High correlation was found between true digestibility and pH-stat method (R²= 0.99). Meaty flavor and gelling properties of veal hydrolysate could make it useful for high-quality soups, sauces and gravies.     

Functional Properties of Veal Bone Hydrolysates

Meat hydrolysates were prepared from crushed veal bone residues, using a commercial preparation of Bacillus subtilis (55°C, pH 7.0). Influence of degree of hydrolysis (DH = 4.0; 5.0; 5.6; 6.2, 8.2%) on functional properties of freeze-dried hydrolysates was studied as compared to sodium caseinate and gelatin, for possible use as natural stock bases for soups, sauces and ready-cooked dishes. Limited proteolysis was controlled using pH-stat and the trinitrobenzene sulfonic acid (TNBS)-methods with strong correlation. Partial hydrolysis improved protein solubility more than 74% over a wide pH range. Emulsifying capacity (EC), activity (EA) and stability (ES) were determined by conductivity measurements. EC and EA increased with protein concentration ranging from 0.025 to 0.25%, while EC decreased with DH. Correlations were high between EA, EC, DH, and adsorption rate.     

Nutrient Content of Special Fed Veal Ribeyes

The nutrient content of special fed veal (SFV) was analyzed and compared to previously reported values for veal and beef. Ribeyes of SFV from 8 different U.S. producers were analyzed for moisture, total fat, protein, cholesterol, folacin, thiamin, riboflavin, niacin, B₆, B₁₂, vitamin A, pantothenic acid, 16 amino acids and 8 minerals. Special fed veal was found to be similar in nutrient content to reported values for beef and veal with one exception; the Fe content of SFV was 14–25% of reported values for beef.     

Sensory colour assessment of fresh meat from pigs supplemented with iron and vitamin E

Pork muscle samples (M. longissimus dorsi) were obtained from pigs given one of four dietary treatments: (1) control diet; (2) supplemental iron [7-g iron (II) sulphate/kg feed]; (3) supplemental vitamin E (200-mg dl-α-tocopheryl acetate/kg of feed); and (4) supplemental vitamin E+supplemental iron. Muscle cores were packaged in polythene bags and placed in a retail refrigerated display cabinet at 5±1°C, under fluorescent light (1000 LUX) for up to 5 days. Samples were subjected to visual colour evaluation by a trained sensory panel (n=12) at 0, 1, 3 and 5 days. In addition instrumental L*, a* and b* values and drip loss were measured on each day of analysis. All samples became less red and browner over storage time in the refrigerated display cabinet. The vitamin E treated samples were more red and less brown compared with the other samples on successive days in the cabinet followed by the control, iron/vitamin E and iron treatments. The iron/vitamin E treatment was positioned midway between the vitamin E and iron treatments indicating that the vitamin E in the samples was effective in reducing the pro-oxidative effect of iron in inducing the brown metmyoglobin pigment development. Iron supplementation did not significantly (P<0.05) increase M. longissimus dorsi iron tissue levels, but had a detrimental effect on the visual sensory properties of the iron and iron/vitamin E treatment groups with greater metmyoglobin formation. Vitamin E appears to have promoted non-supplemental iron absorption in the vitamin E treated group without the detrimental sensory colour characteristics associated with ferrous sulphate supplementation. Drip loss increased in all samples during the course of the experiment with no significant (P<0.05) differences between the experimental groups. The panellists were able to differentiate the four experimental groups on each day of the study and were more effective in evaluating the colour quality of samples than instrumental assessment, i.e. the Hunter L* a* b* method.     

Measurement of Veal Color by Fiber Optic Spectrophotometry

Fiber optic spectrophotometry was used to measure the color of pectoralis profundus, diaphragm, transversus abdominis and adductor muscles in the carcasses of nine veal calves raised commercially for the production of white veal. Blood hemoglobin levels measured before slaughter were correlated with absorbance in the transversus at 1 hr postmortem (r = 0.72, P < 0.05 at 540 nm), but this relationship was obscured by 24 hr postmortem. Pectoralis, diaphragm and adductor increased in paleness between 1 hr and 24 hr postmortem (P < 0.01) as muscle pH declined. In the adductor at 24 hr, pH was correlated (P < 0.01) with absorbance at 10 nm intervals ranging from r = 0.75 at 580 nm to r = 0.91 at 700 nm. The effects of postmortem changes in pH should be taken into account when measuring the paleness of veal.     

犊牛肉生产现状及其分级体系

本文阐述了犊牛肉生产现状及其对我国牛肉产业的意义,介绍了犊牛肉分级研究现状,并为我国相关领域研究给出了建议。     

Protein Recovery from Veal Bones by Enzymatic Hydrolysis

Enzymatic hydrolysis (commercial enzyme) was applied to crushed bones in a batch reactor. The extraction was modeled using a Doehlert design. The effects of temperature (five levels ranging from 40 to 60°C), pH (seven levels from 5.7 to 7.5), enzyme concentration (seven levels from 20 to 80 g.kg^-1 protein), hydrolysis time (seven levels from 30 to 180 mn) and protein concentration (three levels from 60 to 90 g.kg^-1 mixture) were studied. Response surface methodology (RSM) predicted changes in protein yield and hydrolysis degree. Duration and enzyme concentration were the most important parameters, whereas pH and temperature exhibited no significant effects. Inhibition was observed over 80 g.kg^-1 of protein concentration.     

Consumer assessment of the effect of electrical stimulation on the colour and colour stability of Semimembranosus muscles

The influence of effective low voltage electrical stimulation on the colour stability of beef topside (semimembranosus) muscles, during storage and retail display was studied using objective measurements and subjective assessments. Earlier results obtained from objective measurements demonstrated that during a three day retail display period, stimulated topsides had a greater loss of colour than non-stimulated topsides, and primal cuts aged for 33 days at 0 °C before display suffered faster changes to colour during retail presentation than cuts aged for 5 days. To relate results obtained using objective methods to consumer perceptions of meat quality, consumer perceptions of samples of meat displayed for 3 days in the retail cabinets of a major local supermarket were recorded. A total of 960 consumers were asked to evaluate topside steaks for meat and fat colour, meat discolouration and acceptability. During 3 days of retail display, consumers did not perceive differences in the extent of discolouration of topside steaks from electrically stimulated and non-stimulated carcasses; for the majority of the treatment groups (high or low pH muscles, 5 or 33 day ageing, 1-3 day retail display) there were no significant differences, for any of the scored attributes, between stimulated and non-stimulated samples. However, for samples in the fresh (5 days ageing), high pH (5.8-6.0) treatments group, lean meat colour and acceptability for the stimulated samples were, on some of the days on display, given significantly (P < 0.05) better ratings by the consumers than those from corresponding non-stimulated samples.     

Restructuring Veal Steaks with Salt/Phosphate and Sodium Alginate/Calcium Lactate

Quality characteristics of restructured steaks formulated with veal trimmings or veal leg meat and Na-alginate/Ca-lactate or salt (NaCl)/phosphate were evaluated. Trimmings restructured with salt/phosphate had higher (P<0.05) bind scores (measured instrumentally and by sensory) than veal trimmings restructured with Na-alginate/Ca-lactate. Salt/phosphate (0.3–0.5%) reduced (P<0.05) purge and increased binding force and sensory score of bind in restructured veal trimmings and leg meat compared to control and Na- alginate/Ca-lactate treatments. The use of Na-alginate/Ca-lactate as a binder for veal leg meat increased (P<0.05) binding force and sensory score of bind and decreased cook loss when used at 0.4%.     

Selected Nutrients in Ground and Mechanically Separated Veal

Paired samples of ground veal (GV) and mechanically separated veal (MSV) were analyzed for moisture, protein, crude fat, ash, cholesterol, purine bases and nucleic acids. The MSV product was lower than the GV in protein and hypoxanthine and higher in crude fat, ash, cholesterol, adenine and guanine, DNA and total nucleic acids than the ground product. There were no differences between the products in moisture, xanthine, RNA or total purines. The data are limited but indicate that until more data are available, care should be exercised in using high levels of this product in formulations to be consumed by people with a tendency to hyperuricemia or hypercholesterolemia.     

Skin colour assessment in safety testing of cosmetics. An overview

Synopsis
Few subjects are as problematical to dermatologists, cosmetologists and related experimenters involved in safety testing as the clinical assessment of skin colour. At the core of the problem is the word erythema, which does not communicate a sense for the nuance of red. In addition, light shades of red are not visible in dark-skinned people. Human assays aiming at evaluating the irritancy and allergic potential of cosmetics take advantage to use instrumental assessments of skin colour. However, there are pitfalls related to the complex biological aspects of the cutaneous reactivity, to the design of the in vivo assay, and to technical aspects bound to the principle of the measuring methods. Sound information can only be reached when these concerns are solved.
Résumé
Peu de sujets sont aussi problématiques pour les dermatologues, cosmétologues et autres expérimentateurs impliqués dans les tests de sûreté que l'évaluation clinique des couleurs cutanées. Au centre du problème est le mot érythème qui ne communique pas la notion des nuances de rouge. De plus, un érythème discret peut ne pas être visible chez des individus à la peau foncée. Les tests humains visant àévaluer les potentialités d'irritation et d'allergie aux cosmétiques bénéficient des évaluations instrumentales de la couleur cutanée. Cependant, il existe des pièges liés aux aspects biologiques complexes de la réactivité cutanée, au choix du test in vivo et à des aspects techniques en relation avec le principe du système de mesure. Une information adéquate ne peut être obtenue qu'après avoir résolu ces problèmes.     

Collagen and Elastin in Different Cuts of Veal and Beef

SUMMARY– The collagen and elastin content was determined in different cuts of veal and beef. Increases in the amount of total connective tissue are primarily due to increased amounts of collagen, whereas the elastin content is relatively constant. More collagen was found in veal than in beef. The amount of collagen solubilized by heating in one-fourth strength Ringer's solution was twice as high for veal as for beef. Results indicate that the amount of connective tissue proteins in meat is dependent upon the anatomical location and the physiological function of the muscles. Results of chemical and histological analysis are discussed from the standpoint of their nutritional significance.     

Development of caramel colour with improved colour stability and reduced 4-methylimidazole

ABSTRACT

This study investigated the effect of chemical substances, such as Mg²⁺ (as magnesium sulphate), Zn²⁺ (as zinc sulphate), Fe²⁺ (as iron sulphate), ascorbic acid, and citric acid, on the formation of 4-methylimidazole (4-MI) and colour stability of caramel colour. The 4-MI concentration in the caramel colour without chemical substances was 963.10 μg/g, and this decreased the most (67.7%) with the addition of 0.1 molar ratio of citric acid. Colour stability was evaluated by measuring the total colour change (ΔE) after storage, and heating in pH 2, 4, and 7 solutions and 50% solution in ethyl alcohol. Among the chemical substances added to reduce 4-MI in the caramel colour, Mg²⁺ (0.1 molar ratio) and ascorbic acid improved the colour stability more than the others.     

欧盟犊牛福利养殖措施及犊牛肉分级标准

犊牛肉为高档肉品,深受欧美一些国家消费者青睐。本文介绍了欧盟国家为保障犊牛的基本福利采取的福利养殖措施以及犊牛肉分级标准。欧盟先进的养殖措施及分级标准对于有效利用我国丰富的犊牛资源,发展犊牛肉产业具有一定的参考价值。     

GC-MS测定小白牛肉脂肪酸

小白牛肉中脂肪酸的分析尚未见文献报道。采用气相色谱-质谱联用法(GC-MS)检测小白牛肉中的脂肪酸。回流法(90℃,90 min)提取,甲酯化样品中的脂肪,通过与标准对照品和NIST Library谱库比较,得到40种脂肪酸。饱和脂肪酸面积分数为51.165%,以棕榈酸和硬脂酸为主;不饱和脂肪酸面积分数为48.835%,以油酸、亚油酸和花生四烯酸为主。小白牛肉含有丰富的多不饱和脂肪酸,具有较高的营养价值。     

Residues in Young Veal Calves After Consumption of Milk Containing Penicillin

Residues in urine, kidney, and muscle following consumption of milk containing procaine penicillin G were determined in 4-to 8-day-old Holstein bull calves. Calves were fed milk diluted 1:1 with water. Nine control calves received diluted milk only while 8 calves received diluted milk containing 6,600 IU penicillin/kg (low group), and 10 calves received 13,200 lU/kg of milk consumed (high group). Urine samples were collected over 11 h after each morning feeding for 3 days. Calves were slaughtered on day 4 of trial and kidney, muscle, and urine samples obtained. Urine was tested for residues with the Live Animal Swab Test and tissues by the Swab Test on Premises. Both tests are microbiological assays used for detecting growth inhibition of Bacillus subtilis. No residues were detected in urine of control calves. Residues in urine were detected in 6 calves in the low group and 7 calves in the high group after feeding. At slaughter, residues were in 3 of 5 urine samples from calves in the low group and 8 of 10 calves in the high group. However, no residues were detected in kidney or muscle of control or treated calves.     

Evaluation of invasive instruments for assessment of veal colour at time of classification

In a random selection of 480 veal carcasses, invasive measurements were made on the longissimus lumborum (LL) and biceps femoris (BF) with the Colormet, Hennessy Grading Probe (HGP4; LL only) and Invasive Meat Colour Meter. Surface colour of the rectus abdominis (RA) was determined instrumentally with the Minolta Chromameter and Surface Meat Colour Meter and visually by two persons, using a colour standard. All measurements were made at 30-40 min post mortem. Of the measurements made on the RA, the Surface Meat Colour Meter was best related to both visual judgements (r = -0·79; -0·73). The correlation coefficient between both visual judgements was 0·77. Clear differences were found between the invasive instruments in their ability to determine veal colour. The correlation coefficients between the invasive measurements and both visual judgements varied for the Colormet L (?)-value from -0·18 to -0·35, for the HGP4 from -0·40 to -0·49, and for the Invasive Meat Colour Meter from -0·69 to -0·74. Both for LL and BF the best relationships were found between the Invasive Meat Colour Meter and the Surface Meat Colour Meter (RA).