Dry fermented sausages elaborated with lipase from Candida cylindracea. Comparison with traditional formulations

The addition of microbial lipase to fermented sausages was studied. A sausage with lipase from Candida cylindracea and a control sausage with starter (Lactobacillus plantarum and Staphylococcus carnosus) were produced in a pilot plant. The acidity value and the amounts of the different free fatty acids (FFA) showed a higher intensity of lipolytic activity in sausages with lipase than in sausages with starter. In sausages with lipase, the percentage of saturated FFA was greater and that of polyunsaturated FFA was lower than in sausage with starter. Mono-unsaturated FFA percentage was similar in both sausages. TBA and peroxide values indicated that the increase of FFA produced by lipase action did not increase the rancidity. A slight increase in acetic, propionic and butyric acids was observed in sausage with lipase but this was not sufficient to develop excessive acidity in the product.     

响应面法优化脂肪酶的固定化条件及其水解橄榄油的特性研究

采用Sepharose CL-4B和7种大孔树脂为载体固定Palatase 20000L脂肪酶,对载体进行筛选,以酶活力为指标,采用响应面法优化固定化条件,并考察所制得固定化酶的稳定性和水解橄榄油的酶学性质。结果表明：以大孔树脂HPD-600为载体制得的固定化酶具有较高的活性和良好的稳定性。其最优的固定化条件为：pH3.9,酶与载体比例为9.1mg/g,吸附时间1.8h。在最优条件下制得固定化酶在最适合条件下测得的酶活力达到1440U/g,酶活回收率大于50%。固定化酶最适作用温度为50℃,最适作用pH值为8.0。固定化酶的Km值为0.130g/mL,高于游离酶的Km(0.069g/mL)。固定化酶的热稳定性有一定程度的提高,其重复操作5次后相对酶活力仍保持在58%以上。     

Effect of the addition of pancreatic lipase on the ripening of dry-fermented sausages - Part 2. Free fatty acids, short-chain fatty acids, carbonyls and sensory quality

The effect of the addition of nine different amounts (3–500 units) of pancreatic lipase on the composition of free fatty acids (FFA), short-chain fatty acids and carbonyls, as well as the sensory quality, has been studied on dry fermented sausages. The lipase produced a greater release of all fatty acids in relation to the control sausages. The greater the pancreatic lipase content, the higher the release of these fatty acids, the most important ones being myristic, palmitoleic and oleic acids. A lower release of linoleic acid was observed, probably because of its oxidative degradation. At the end of the ripening in all lipase-added batches, a clear increase of the carbonyl content was noticed in relation to conventional sausages. No consistent changes were observed in the short-chain fatty acid fraction. In the sensory evaluation, the highest significant differences (P < 0·01) between control sausages and lipase-added batches were observed when 60 and 90 lipase units were used. According to the chemical and sensory analyses, it can be concluded that the addition of 60 and 90 units to sausages seems to be useful to enhanced the flavour of these products.     

Acceleration of Cheddar Cheese Lipolysis by Using Liposome-entrapped Lipases

ABSTRACT: Two types of lipase (Palatase M and Lipase 50) were encapsulated in liposomes with trapping efficiencies of 35.9 and 40.3%, respectively. The lipases were incorporated into cheese milk at levels of 0.2, 0.5, and 1.0 lipase units/g fat. Treated cheeses had higher moisture and lower protein, fat, and ash contents than the control cheese and they were less firm, but more elastic and cohesive, than the control cheese. Production of free fatty acids was accelerated by the addition of encapsulated enzymes. Cheeses with up to 0.5 lipase unit/g milk fat had slightly better flavor intensities than control cheese. Cheeses with the highest level of Palatase M and Lipase 50 developed a pronounced soapy off-flavor after 2 and 3 mo of ripening, respectively.     

接种植物乳杆菌和蔗糖添加量对发酵香肠品质特性的影响

研究接种植物乳杆菌6003和蔗糖添加量（0.4%和1.5%）对发酵香肠品质的影响。结果表明：接种植物乳杆菌6003,可加速发酵过程中pH值的降低;发酵香肠的硫代巴比妥酸反应物（thiobarbituric acid reactive substances,TBARs）值和总挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量显著降低（P＜0.05）;发酵香肠菌落总数和乳酸菌数在发酵过程中迅速增加（P＜0.05）,在贮藏期间显著减少后趋于平稳,且菌落总数和乳酸菌数显著高于自然发酵香肠（P＜0.05）;此外,接种后的发酵香肠具有更高的硬度及总体可接受度评分,颜色无显著变化。发酵后,随着贮藏时间的延长,各组发酵香肠的pH值和可滴定酸度无显著变化,黏聚性、亮度值、红度值和水分活度显著降低,黄度值、TBARs值、TVB-N含量、硬度、咀嚼度和胶着度显著升高;不同添加量蔗糖对发酵香肠相关参数的影响较小。因此,选择蔗糖添加量0.4%和植物乳杆菌6003接种量7（lg（CFU/g））的方法生产发酵香肠较为适宜。     

微生物发酵与酶法结合制备天然奶味香基的研究

选用具有丁二酮合成能力的乳酸乳球菌NRRL B-2356发酵全脂乳与脂肪酶结合制备天然奶味香基。乳酸乳球菌NRRL B-2356发酵全脂乳丁二酮、3-羟基丁酮产量在27h时达最大(52.95μg/mL),与德氏乳杆菌混合发酵,两者接种量比值为5:1时,丁二酮、3-羟基丁酮含量达60.1μg/mL,香气评分最高。利用脂肪酶palatase2000L对发酵液进行酶解修饰以提高香气强度,酸值为6.73mgKOH/g时香气评分最高。同时蒸馏萃取装置与GC-MS结合对奶味香基中挥发性成分进行了分析,结果表明,游离脂肪酸为98.586%,酮类1.219%,内酯类0.142%。研究制备的奶味香基香气纯正浓郁,可用于调配高档奶味香精。     

Simultaneous addition of Palatase M and Protease P to a dry fermented sausage (Chorizo de Pamplona) elaboration: Effect over peptidic and Lipid fractions

The effect of the simultaneous addition of a lipase (Palatase M 200L Novo Nordisk A/S) and a protease (Protease P 31.000 Solvay Enzymes GMBH&CO.KG) to the manufacture of a Spanish dry fermented sausage (Chorizo de Pamplona) was studied. In relation to the free aminoacid fraction, significative increases in Glu, His, Lys, Ser, Ala, Pro, Val, Met, Ile, Leu and Phe were found. Smaller differences were observed in the aminoacids obtained from peptides. The addition of the lipase caused significant increases in palmitic, oleic and linolenic acids. Despite the observed changes, no differences were found in the sensory quality compared with the control, except for a slight softening.     

浓缩型冻干发酵剂在鸭肉发酵香肠中的应用

将浓缩型冻干发酵剂应用于鸭肉发酵香肠中,对比液体发酵剂和自然发酵对香肠发酵过程中的影响。结果表明：接种冻干发酵剂的香肠48 h内pH值降到5.3以下,能够快速发酵产酸达到发酵香肠安全控制范围,且水分含量呈下降趋势,发酵末期降到30%左右;对各处理组鸭肉香肠的质构进行分析比较,接种冻干发酵剂处理组（S2处理组）以及液体发酵剂（L2处理组）的香肠硬度、弹性和咀嚼性均显著（P＜0.05）高于自然发酵（对照组）;此外,香肠发酵过程中酸价呈上升趋势,过氧化值先上升后下降,各处理组差异不显著（P＞0.05）,推断内源性脂酶比微生物发酵剂产生的脂酶发挥更大作用;各类型脂肪酸占总游离脂肪酸的比例大小顺序为：饱和脂肪酸＞单不饱和脂肪酸＞多不饱和脂肪酸,接种发酵剂的处理组游离脂肪酸总量显著高于对照组（P＜0.05）,表明发酵剂的添加对游离脂肪酸的释放起到一定促进作用,在一定程度上丰富了香肠风味的前体物质。     

微生物酶与肉组织酶对干发酵香肠中游离脂肪酸的影响

以戊糖乳杆菌31-1和木糖葡萄球菌为发酵剂生产干发酵香肠,就发酵剂对干发酵香肠成熟过程中游离脂肪酸的影响进行了研究。研究结果表明,在灌肠后的1周内,脂肪的水解主要是由组织酶引起的,微生物对脂肪微弱的水解能力主要表现在干发酵香肠成熟的后期,并且发酵剂不能改变发酵香肠中游离脂肪酸的变化模式。     

Chemical Profiles of Hydrolyzed Milk Samples after Treatment with Commercial Enzymes

ABSTRACT: Commercial enzymes (protease and lipase) were used to produce highly flavored cheese-like hydrolysates from fluid milk. Free fatty acids, free amino acids, degree of proteolysis, and volatile profiles were assessed to suggest the importance of proteolytic and lipolytic activity on cheese flavor development. Free fatty acid liberation was maximized with the combined Flavourzyme™ (protease) and Palatase ® (lipase) treatment incubated at 30°C, most likely due to synergism conferred by the protease. The Flavourzyme/Palatase samples incubated at 45°C generated the highest total concentration of volatile compounds. The addition of Flavourzyme generated free amino acids and low molecular weight peptides (< 1400 MW).     

Prevalence of Listeria monocytogenes in fresh and fermented Italian sausages and ribotyping of contaminating strains

Listeria monocytogenes has been detected in fresh as well as dry and semidry fermented sausages, rendering preparation and consumption of these products as a potential risk to human health. The aims of this study were (1) to evaluate the L. monocytogenes prevalence in 288 fresh and 237 fermented sausages produced in northern Italy; (2) to quantify the average pathogen Most Probable Number (MPN) per g of sausage; (3) to evaluate the sausage strain genetic diversity by automated PvuII ribotyping; and (4) to predict the pathogenicity lineage of these isolates determining their DuPont Identification Library Codes (DUP-IDs) by EcoRI ribotyping. The overall prevalence of L. monocytogenes in the sampled sausages was 28.2%. The percentage of L. monocytogenes positive fresh sausages was significantly higher than that of fermented sausages (i.e. 38.9 vs 15.2%), which had a pathogen load always lower than 10 MPN/g. In contrast, 16.1% of fresh sausages were contaminated by 10 to 100 MPN/g and 20.5% had more than 100 MPN/g. PvuII successfully discriminated sausage isolates with a Simpson's numerical index of discrimination of 0.637. A total of 12 and 9 different PvuII ribogroups were identified among 47 fresh and 24 fermented randomly selected sausage strains, respectively. Six of those ribogroups were shared between strains contaminating both kinds of sausages. According to the evaluation of the strain DUP-IDs, the majority of the isolates investigated in this study were part of the type II L. monocytogenes pathogenicity lineage, but type I lineage strains were identified among fermented sausage isolates. In conclusion, L. monocytogenes prevalence in Italian sausages was estimated to be around 28.2%. However, 84.2% of the samples were contaminated by less than 100 MPN of L. monocytogenes per g and the majority of L. monocytogenes contaminating strains would be classified in the type II pathogenicity lineage, including serotypes 1/2a, 1/2c and 3a.     

Improvement of nutritional properties of Chorizo de Pamplona by replacement of pork backfat with soy oil

Dry fermented sausages with a partial substitution of 15, 20 and 25% of pork backfat by pre-emulsified soy oil were prepared. No differences were detected in the water, protein and fat content between control and modified sausages. Cholesterol amount scarcely decreased in the modified sausages (92.96 mg/100 g product in control sausages, 87.71 mg/100 g in sausages prepared with 25% of substitution). No increase in oxidation was detected through chemical or sensory analysis in modified sausages. Saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) in control products were 37.83 and 45.78 g/100 g of total fatty acid, respectively, decreasing in the modified formulations, to 32.81 and 42.09 g/100 g of total fatty acid in the 25% replacement products, respectively. Polyunsaturated fatty acids (PUFA) increased from 15.22 (control) to 23.96 g/100 g of total fatty acid (25% product) due to the significant increase in linoleic and -linolenic acids when soy oil was added. In relation to texture profile analysis (TPA), hardness and springiness did not show significant differences among products. The instrumental measured colours were comparable with that of commercial products. Sensory evaluation of most of the modified sausages did not show significant differences with regard to the control.     

降胆固醇乳酸菌的筛选及其在内蒙古发酵香肠中的应用

通过对乳酸菌降胆固醇生物学特性及对发酵肉制品中胆固醇降解作用进行研究,结果表明,从内蒙古传统肉肠中分离筛选得到的8 株乳酸菌中,菌株X3-2B有较强的胆固醇降解能力。且在MRS培养基中添加3 g/L胆盐、20 g/L胆固醇和 20 g/L葡萄糖时菌株X3-2B的胆固醇降解能力最大,在不同培养基中发酵不同时间菌株X3-2B对胆固醇的降解能力显著高于标准菌株。在以菌株X3-2B为发酵剂的发酵香肠中,其胆固醇含量显著低于对照组。故菌株X3-2B可作为一株降胆固醇性能较好的肉制品发酵剂。     

肉用发酵菌株的筛选及其在低盐发酵香肠中的应用

该研究以蛋白酶、脂肪酶活性和抑菌活性筛选肉用发酵菌株,通过分子生物学技术对其进行鉴定,并将其应用于低盐发酵香肠中,通过感官、理化及微生物指标分析评价其应用效果。结果表明,筛选鉴定得到两株适用于肉类发酵、安全且具有蛋白酶及抑菌活性的菌株,分别为植物乳杆菌（Lactiplantibacillus plantarum）BR-12和木糖葡萄球菌（Staphylococcus xylose）H-1,其中菌株BR-12还具有脂肪酶活性,两菌株间无拮抗作用。菌株BR-12与H-1按2∶1和1∶5的比例接种制备的低盐发酵香肠pH下降迅速,肠杆菌数与挥发性盐基氮含量较低,感官评分较高,硬度适中,弹性好,呈特有的玫瑰红色,且两菌株接种比例为2:1时,品质更好,说明菌株BR-12和H-1复配发酵有利于提高产品安全性,改善低盐发酵香肠滋气味,可用于低盐香肠发酵。     

Lipid Fractions of Dry Fermented Sausages Change when Starter Culture and/or Aspergillus Lipase are Added

Six levels of Aspergillus sp. lipase were evaluated and 0.400u/g was selected. A sausage with a starter culture (Lactobacillus plantarum (10%)+Staphylococcus carnosus (90%)), one with lipase and one with both starter culture and lipase were produced in a pilot plant. A lower amount of Micrococcaceae was found in sausages without starter culture. Total FFA quantity at the 15th day was higher in sausages with lipase. Higher amounts of acetic, propionic and butyric acids were found in sausages with both lipase and starter culture. Odor intensity had slightly higher scores in sausages with added lipase.     

脂肪酶对中式香肠脂肪降解、氧化和风味的影响

为提高高温短时烘烤的中式香肠品质,本实验研究了添加量为肉质量0.00%、0.02%、0.04%、0.06%、0.08%和0.10%水平的脂肪酶（Palatase）对中式香肠脂质降解、脂肪氧化、挥发性风味物质和感官品质的影响。结果表明：添加脂肪酶能有效加速中式香肠中的脂肪降解和脂肪氧化,促进香肠中脂质来源的挥发性风味物质的生成。添加适量（0.06%）外源脂肪酶能使香肠香气显著增强,并且不影响香肠的其他感官品质;过量添加外源脂肪酶则会导致香肠过度氧化,影响感官品质。     

不同菌种组合对发酵广式香肠品质的影响

广式腊肠为我国传统特色肉制品,深受广大消费者的喜爱。随着对我国传统肉制品品质、安全性和现代加工技术的重视,对广式腊肠的研究逐渐增多,但对发酵剂用于广式香肠的研究相对较少。本文以植物乳杆菌、戊糖片球菌、汉逊德巴利酵母为发酵剂制作发酵广式香肠,研究了不同发酵剂组合对发酵广式香肠理化性质的影响,结果表明不同比例组合发酵剂对发酵广式香肠品质影响不同,当菌种的接种量为106 cfu/g肉时,由植物乳杆菌和戊糖片球菌组合的发酵剂(2:1,V/V)时,发酵的香肠品质最佳,其水分含量为19.93%,pH值为5.95,总酸含量为35.6 g/kg,酸价为3.38 mg/g,过氧化值为0.059 g/100 g,亚硝酸盐残留量为4.46 mg/kg,弹性为0.93,硬度为9498.86 N,粘聚性为0.79,咀嚼性为6917.93 N,L*值为50.86,a*值为6.66,b*为3.87。采用复合菌剂生产的肉制品的理化特性明显优于自然发酵的肉制品。     

发酵剂对发酵香肠食用品质的影响及其在不同直径香肠中的应用

以商业发酵剂(木糖葡萄球菌+戊糖片球菌)为对照组,不同发酵剂组合(木糖葡萄球菌+副干酪乳杆菌、木糖葡萄球菌+戊糖片球菌+副干酪乳杆菌)为实验组,通过对发酵香肠水分含量、pH值、水分活度、色泽、质地、风味和感官品质等指标进行测定,确定最佳发酵剂及适宜发酵的香肠直径。结果表明:相较于商业发酵剂,木糖葡萄球菌与副干酪乳杆菌组合发酵的香肠总体可接受性相对较高,且庚醛、1-辛烯-3-醇、乳酸乙酯、戊酸乙酯、癸酸乙酯、2-甲基丙酸乙酯等愉悦风味物质为该组独有,其特征主要表现为更加浓郁的清新味、甜香味、果香味和花香味;适宜的直径(21 mm)、水分含量((25.40±0.00)%)和硬度((2 812.46±767.93)g)以及相对较高的pH值(pH 5.57±0.02)是该组发酵香肠口感显著高于其他2组的重要原因。因此,木糖葡萄球菌与副干酪乳杆菌组合发酵的小直径香肠食用品质最佳。     

Effect of E-beam treatment on the bioaccessibility of folic acid incorporated to ready to eat meat products

Meat products are a potential matrix to fortify with folic acid (FA). In previous studies the effect of E-beam treatment on the stability of FA in ready to eat (RTE) meat products has been described. However, the FA bioaccessibility in both traditional and treated (3 kGy) RTE meat products has not yet been studied. We investigated the availability for intestinal absorption (bioaccessibility) of FA using a dynamic gastrointestinal model (TIM system). Three different types of meat products, hamburgers, cooked sausages and dry fermented sausages, initially fortified with 24 μg/g FA were tested as freshly prepared products and as RTE products. The bioaccessibility of FA during the passage through the TIM system was high for all three products, irrespective the E-beam treatment. From hamburgers the bioaccessibility was 82% and 100%, from cooked sausages, 61 and 79% and from dry fermented sausages 81 and 82%, with or without e-beam treatment, respectively.     

Preliminary analysis of the lipase gene (gehM) expression of Staphylococcus xylosus in vitro and during fermentation of naturally fermented sausages (in situ

Coagulase-negative catalase-positive cocci (CNCPC) play a very important role during the fermentation of sausages. In particular, they are involved in the aroma formation of the final product, because they release lipases that are able to free short-chain fatty acids that are contributing to the sensory characteristics of the fermented sausage. Few studies have been undertaken to elucidate the regulation of lipase gene expression in Staphylococcus xylosus by substrate molecules or products of lipolysis. The aim of this study was to analyze the gehM gene expression of S. xylosus DSMZ 6179 in vitro with growth media containing different concentrations of lipids and in situ during the maturation of fermented sausages. The results obtained suggest that a concentration that increases in triglycerides in the growth medium suppresses the expression of the lipase gene.