木瓜蛋白酶对牛肚嫩化品质效果的影响研究

利用正交试验法优化木瓜蛋白酶的嫩化处理工艺。以剪切力为指标,以酶添加量、pH值、嫩化温度和嫩化时间为主要考察因素,采用正交试验法优化木瓜蛋白酶嫩化处理的最佳工艺参数。结果表明,木瓜蛋白酶嫩化处理的最佳工艺条件为:pH值5,嫩化时间30min,嫩化温度40℃,酶添加量500U/g。该工艺条件下,剪切力为4 857g·s。本试验可为牛肚的嫩化处理提供参考。     

嫩化型五香风味牛肉干的研制

目的研制嫩化型五香风味牛肉干。方法以剪切力值为评价指标,利用单因素与正交试验确定木瓜蛋白酶、复合磷酸盐和氯化钙的最佳复合配比;以感官评分为评价指标,采用单因素试验与正交试验确定嫩化温度、嫩化时间、复煮时间与烘干时间的最佳工艺参数。结果复合嫩化剂最佳配比为:木瓜蛋白酶0.03%、复合磷酸盐0.3%、氯化钙1%,嫩化后的剪切力值降低,符合肉的可接受范围。最佳工艺参数为:嫩化温度55℃、嫩化时间3 h、复煮时间60 min、烘干时间3.5 h,此条件下感官评分最高。结论根据上述最佳复合配比嫩化剂和最佳工艺参数制得的嫩化型五香风味牛肉,干色泽棕黄,甜咸适中,风味独特。     

超声波协同复合嫩化剂对生鲜猪肉嫩度的影响

采用超声波协同氯化钙及复合磷酸盐(三聚磷酸钠、六偏磷酸钠)对生鲜猪肉进行嫩化后,以植物蛋白酶(木瓜蛋白酶、菠萝蛋白酶)对其进行酶法嫩化,在单因素试验基础上通过正交试验,以剪切力为考察指标,探讨生鲜猪肉最优嫩化工艺条件。结果表明:超声功率、超声时间、复合磷酸盐添加量、植物蛋白酶添加量、酶作用温度影响显著,氯化钙添加量及水浴时间影响不显著,各因素对剪切力影响的主次关系为超声时间植物蛋白酶添加量超声功率酶作用温度复合磷酸盐添加量氯化钙添加量水浴时间。功率150 W条件下超声处理25min、1.0%氯化钙、0.20%复合磷酸盐、0.03%植物蛋白酶、酶作用温度20℃、水浴30 min,生鲜猪肉剪切力最小,肉最嫩。     

响应面法优化预调理火锅牛肉酶法嫩化工艺

针对预调理火锅牛肉的嫩化工艺,采用木瓜蛋白酶和中性蛋白酶进行复配,研究2种酶的复配比例、复合酶添加量及酶处理时间对牛肉持水力和硬度的影响.在单因素试验基础上,采用响应面优化设计对工艺条件进行优化,确定复配酶法嫩化最佳工艺条件为:木瓜蛋白酶和中性蛋白酶复配比例1:1.19、复合酶添加量0.085％、酶处理时间3.1?h,...     

响应面法优化超声波辅助姜汁嫩化炸猪排工艺

采用超声波辅助生姜汁嫩化,通过单因素试验结合响应曲面优化法,对炸猪排的感官品质、质构、剪切力、pH值、持水力等指标进行测定,研究炸猪排的嫩化工艺。结果表明：经优化后的炸猪排嫩化条件为姜汁体积分数29.57%（添加量2.5 mL）、超声时间31.54 min、超声功率61.35 W,在此条件下炸猪排剪切力预测值为24.41 N,感官评价为8.9 分,与对照组（7.4 分）相比提高33.7%;验证实验表明,模型预测结果与实际值吻合,模型有效。     

响应面法优化木瓜蛋白酶-复合磷酸盐嫩化低档部位牛肉工艺

采用响应面回归设计来探究复合磷酸盐与木瓜蛋白酶复配使用嫩化低档部位烧烤牛肉的最佳条件。以单位肉中木瓜蛋白酶活力、复合磷酸盐质量浓度和作用时间为嫩化因子,以剪切力值和感官评价得分为响应值,运用Design-Expert 8.05软件对测得的结果建立二次回归模型。结果表明,复合磷酸盐与木瓜蛋白酶配合使用可以有效降低中低档部位牛肉的剪切力值,同时适当减少酶的用量,提高肉的保水性,得到更好的感官评价效果。最佳嫩化条件为：木瓜蛋白酶活力9.44 U/g、复合磷酸盐质量浓度18.35 mg/mL、作用时间9.09 h。在此条件下,低档部位烧烤牛肉的剪切力预测值为17.25 N,感官得分为5.02,整体感受较满意。经过实验验证,实测值与预测值吻合良好,说明响应面模型具有较好的预测能力,能有效用于剪切力值和感官评分的预测。     

木瓜蛋白酶与超高压技术嫩化驼肉的研究

研究木瓜蛋白酶和超高压嫩化处理对双峰驼腱子肉的嫩度及营养品质的影响。对木瓜蛋白酶浓度、溶剂pH值、嫩化温度、嫩化时间、超高压压力水平、压力时间进行单因素实验，通过测定骆驼肉的蒸煮损失、系水力、pH值、色泽、质构特性和最大剪切力，筛选两种处理方式嫩化骆驼肉的最佳条件。通过L9(34)正交试验筛选出驼肉的最佳嫩化工艺，结果表明：驼肉经木瓜蛋白酶和超高压嫩化处理后嫩度均有所提高，木瓜蛋白酶的最佳嫩化条件为：酶浓度120 U/mL，溶剂pH 6，嫩化温度55℃、嫩化时间2 h；超高压最佳嫩化条件为：压力250 MPa、处理时间20 min。经木瓜蛋白酶嫩化的驼肉剪切力有明显降低，超高压嫩化的效果虽没有酶嫩化效果明显，但能较好地保护肉中的营养物质。研究结果为畜禽肉的相关嫩化技术的应用提供参考依据，也为后续驼肉及其相关产品的开发奠定了基础。     

辅料黏合剂的添加对调理猪排品质的影响

以猪颈背肉为主要原料,研究转谷氨酰胺酶(TG)、酪蛋白酸钠(SC)、复配胶(卡拉胶和魔芋胶1:1)对调理猪排品质的影响。通过单因素实验,研究转谷氨酰胺酶、酪蛋白酸钠、复配胶的添加对调理猪排剪切力、离心损失、蒸煮损失、水分含量、色差、出品率、感官评分的影响。在单因素实验的基础上,进行响应面试验,确定粘合剂的最优添加量。单因素结果表明,TG添加量为0.60%时,保水性及感官评分最高,酪蛋白酸钠添加量为0.10%,或复配胶(卡拉胶和魔芋胶1:1)添加量为0.20%时,既能保证适宜的嫩度与保水性,感官评分也最高。响应面试验结果表明,在转谷氨酰胺酶添加量为0.70%、酪蛋白酸钠添加量为0.07%、复配胶添加量为0.21%时,所加工的调理猪排的感官评分最高,总分60分时,得分为55.54。     

正交优化生鲜调理鸡肉胰蛋白酶嫩化工艺

利用正交试验法优化生鲜调理鸡肉胰蛋白酶的嫩化处理工艺。以剪切力为指标,以酶浓度、嫩化温度和嫩化时间为主要考察因素,采用正交试验法优化胰蛋白酶嫩化处理的最佳工艺参数。结果表明,胰蛋白酶嫩化处理的最佳工艺条件为:酶浓度0. 04g/100mL,嫩化温度50℃,嫩化时间1. 5h。该工艺条件下,剪切力为9. 7N。本试验可为调理鸡肉的嫩化处理提供参考。     

木瓜蛋白酶结合滚揉处理对马肉嫩度的影响

以系水力、蒸煮损失和剪切力为评价指标,结合滚揉处理,研究了木瓜蛋白酶在不同的添加量、p H值、处理温度和处理时间下对马肉嫩度的影响,并利用正交试验优化出了木瓜蛋白酶最佳嫩化条件。实验结果表明:木瓜蛋白酶的添加量、p H值、处理温度和处理时间对马肉的系水力、蒸煮损失和剪切力均有显著的影响;在木瓜蛋白酶的添加量15 U/g,处理温度50℃,p H 6.0,处理时间1 h;或者木瓜蛋白酶添加量为10 U/g,处理温度50℃,p H 6.0,处理时间1.5 h的条件下,添加木瓜蛋白酶均能达到理想的嫩化效果。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the