The effect of inulin supply to high‐fat diet rich in saturated fatty acids on pork quality and profile of sarcoplasmic protein in meat exudate

The aim of the study was to evaluate the influence of inulin supply to high‐fat diet rich in saturated fatty acids (SFA) on pork quality and profile of sarcoplasmic protein in drip loss. At 50 days of age, twenty cross‐bred pigs (gilts) were randomly allotted to four groups: the control (C) group fed a standard diet, and three experimental (D1, D2 and D3) groups fed a high‐fat diet rich in SFA. Moreover, pigs from the groups D2 and D3 consumed an extra inulin supply (7% of daily feed intake) from 85 to 120 days of age (for 5 weeks) and from 50 to 120 days of age (for 10 weeks) respectively. The addition of inulin to the diet reduced meaty odour and flavour significantly, improved tenderness and overall sensory quality of pork and additionally influenced ultimate pH, L* colour parameter, lactate level and protein content in meat. The diets also affected the profile of sarcoplasmic proteins. Significant effects were observed for the following enzymes—PK/PGI (pyruvate kinase/phosphoglucose isomerase) and ALD (aldolase), which are related to the intensity of post‐mortem glycolysis. Presented data indicate that long‐term inulin supply to high‐fat diet has a positive effect on technological and sensory quality as well as protein profile of pork.     

杜长大猪肉品质性状间相关性分析

为了探讨猪肉品质性状间的相关关系,试验选取86头杜长大猪的背最长肌进行部分肉质性状测定。结果表明:大理石纹与肉色有极显著正相关关系(P<0.01),与肌内脂肪有显著正相关关系(P<0.05);拿破率与失水率有显著负相关关系(P<0.05),与pH24有极显著正相关关系(P<0.01)。结论:研究发现测定的猪肉品质的指标间相互存在着重要联系,为更好地提升猪肉的品质提供新的思路和依据。     

Optimization and physicochemical properties of nutritional protein isolate from pork liver with ultrasound‐assisted alkaline extraction

The aim of this study was to investigate the optimal conditions of ultrasound‐assisted alkaline extraction (UAAE) on pork liver protein isolate (UPLPI) and its physico‐chemical properties. Response surface methodology was used to determine the optimal conditions for UAAE, which were at ultrasonic power 265 W, ultrasonic time 42 min, NaOH concentration 0.80%, temperature 50°C, and solvent/raw material ratio 70. The extraction yield and efficiency of UPLPI were significantly improved over the conventional alkaline extraction (PLPI). The results of amino acid composition showed that UAAE could increase serine (36.5 g/kg), arginine (38.1 g/kg), alanine (37.5 g/kg), proline (48.7 g/kg), phenylalanine (55.6 g/kg) and lysine (47.2 g/kg) elution amount. The changes in fourier transform infrared spectra indicated unfolding and destruction of the protein structure in UPLPI. The differential scanning calorimetry analysis presented UPLPI with a slightly lower onset and peak denaturation temperature over PLPI. Surface hydrophobicity increased and the microstructures presented larger and more pores of UPLPI, therefore, it had better in vitro digestibility than PLPI. Therefore, UPLPI might have a potential application prospect in the food field due to its changes on molecular structure as well as on the microstructure of protein by UAAE.     

2013年1—3季度中国生猪市场分析及展望

2012年9月～2013年8月，能繁母猪存栏量几乎连续1年均维持在5000万头以上，生猪产能充足。2013年春节后国内猪价一路下滑，3个月下跌近三成，创2010年8月中旬以来最低水平。受政府收储等影响，猪价5．6月反弹。夏季持续高温天气、养殖户惜售等导致生猪供应量出现阶段性减少，全国猪价“淡季不淡”，至中秋节，价格连续上涨回升三成。中秋节、国庆节期间，市场流通领域猪肉（鲜猪肉和政府投放的冷冻储备肉）供应充足．而需求反弹力度有限，猪市承压弱势波动。随着生猪饲养方式的不断转变和产业结构调整，生猪养殖规模化、标准化发展步伐逐步加快，生猪养殖已进入微利时代，猪周期具有延长趋势。随着节后生猪供应量减少以及需求旺季到来，如果没有重大疫情扰乱市场供应，至2014年春节前的数月，可能会出现连续震荡上涨，但总体稳定，不会出现大幅波动．     

环保猪肉的消费者行为分析

消费者对环保猪肉的消费能否实现买前判定、买时决定、买后安定、吃得镇定、食后肯定,不仅决定环保猪肉的市场前景,而且也直接影响到现代生猪产业的发展。本研究采用拦截样本取样法,并深入剖析了138位被调查者对环保猪肉的消费行为。结果表明:大多数消费者对环保猪肉的认知程度较低,对其安全性还心存疑虑;大多数消费者对环保猪肉有较强的购买愿望,说明消费者对猪肉消费安全非常重视,并愿意为环保猪肉支付更高的价格。研究还表明,信息满意度、消费者收入水平、文化程度、年龄、性别是影响环保猪肉消费者支付意愿的主要因素。最后提出:只有生猪产业链上各个利益主体共同努力,营造一个安全、健康、科学的环保猪肉消费环境,才能促进现代生猪产业的健康发展。     

日粮中添加沼渣对猪肌内脂肪酸组成及含量的影响研究

试验选择18头杜×长×大三元杂交猪为试验材料，研究了日粮中添加沼渣对猪肌内脂肪酸组成及含量的影响。结果显示，除背最长肌中油酸含量有显著差异外，其余脂肪酸的含量无显著差异。通过分析认为，日粮中添加沼渣不会从肌内脂肪酸组成及含量上对猪肉风味及其他肉质性状产生不利影响，但需要注意日粮中添加过高比例的沼渣可使猪肉中多不饱和脂肪酸增多，有导致肉品质变差的倾向。     

酱卤肉中亚硝酸钠含量的测定

采用盐酸萘乙二胺分光光度计法对酱卤肉中亚硝酸钠含量进行了测定,考查了制样的均匀性、饱和硼砂用量、显色剂新鲜度和标准曲线不同等因素对试验结果产生的影响。结果表明,采用四分法均匀取样粉碎混匀,加入饱和硼砂12.5 mL,沸水浴加热15 min,显色剂现配现用,选用合适的标液,以保证检验结果的准确性。     

Droplet digital polymerase chain reaction assay for identifying and quantifying pork products

Halal products are growing in consumer markets worldwide, and pork meat is classified as non-halal. Manufacturers of processed foods and products must ensure that their products follow Islamic dietary law because pork is prohibited for Muslims. Droplet digital polymerase chain reaction (PCR) (ddPCR) is a novel method for identifying pig species and quantifying pork products. This experiment aimed to investigate pork species and establish the proportion of pork in meat products using the mitochondrial cytochrome b gene (CYTB). The study found that the correlation coefficient between the meat weight and DNA concentration of pork was 0.997, and the correlation coefficient between the DNA concentration and the target DNA copy number of pork was 0.998. The accuracy of the ddPCR assay was verified using a sample of a known proportion of pork, and it was revealed that this method is highly precise in quantifying pork products. Nine products contained an undeclared meat proportion (90%). The limit of detection for pork was 0.0001 ng. The analysis indicated that the ddPCR assay has high accuracy and sensitivity for quantifying pork products. Therefore, the predictive model can be used in routine laboratories for quality assurance of halal food products.     

Nonlinear dynamics of pork price in China

This paper primarily analyzes the evolution path of China’s pork price by employing the threshold autoregression model (TAR). Considering the unit root test with a threshold effect and heteroskedastici...     

猪肉市场调控措施及其效果研究

猪肉市场的调控已成为关系民生和民心的重大问题,也成为政府应对通胀和稳定供应的重大课题。2007年起中国政府加大对猪价调控,但猪价的周期性波动却愈演愈烈。作者通过分析可知,针对流通环节的猪肉储备政策能够在一定程度上稳定猪价,但针对生产环节的调控措施则无论是在力度上还是方向上都和预期效果产生了较大的偏差,其综合效果反而加剧了猪价的波动。研究政府对猪肉市场调控措施的效果,作者提出需要将生产环节的调控措施和流通环节的调控措施分开来分析评价。