分步酶解法制备酶改性切达干酪粉

介绍了一种分步酶解法制备酶改性干酪粉(EMC)的方法。第一步,用不同的蛋白酶与肽酶混合酶对切达干酪浆进行蛋白水解,筛选出最佳水解产物。第二步,用不同的脂肪酶对最佳水解产物进行脂肪水解。将得到的酶解液喷雾干燥获得两种粉末状的EMC产品A和B,并与商品切达EMC进行比较分析。本研究获得的两种EMC产品的总游离氨基酸及总游离脂肪酸质量分数均比商品EMC高,各种游离氨基酸质量分数也普遍高于商品EMC。EMC产品A感官指标得分较高,不同链长的脂肪酸比例与商品EMC接近。     

Flavouring of imitation cheese with enzyme-modified cheeses (EMCs): Sensory impact and measurement of aroma active short chain fatty acids (SCFAs)

Enzyme-modified cheeses (EMCs) are used to impart flavour to imitation cheese products. Cheeses (pH 6 or 5.5) were formulated with 5% w/w EMC, having low, medium or high levels of lipolysis and were examined by a sensory panel. Free fatty acid analyses were performed using SPME/GC. The flavour profile of the flavoured cheeses was affected by EMC composition and pH of the cheese base. Cheeses at a pH of 6.0, flavoured with low lipolysis EMCs, were described as ‘bland’. Lowering the pH of the cheese matrix to 5.5 appeared to increase the flavour intensity of the cheese flavoured with low lipolysis EMC and panellists ranked this cheese the highest, describing its flavour as ‘well-balanced and ‘cheesy’. This study shows that the flavours of imitation cheeses are influenced by the level of lipolysis of the EMCs used to flavour them and also by the pH of the cheese base.     

A survey of lipolytic and glycolytic end-products in commercial Cheddar enzyme-modified cheese

The concentrations of L- and D-lactic acid and free fatty acids, C4:0 to C18:3, were quantified in a range of commercial enzyme-modified Cheddar cheeses. Lactic acid in Cheddar enzyme-modified cheeses varied markedly depending on the manufacturer. Differences in the ratio of L- to D-lactic acid indicate that cheeses of different age were used in their manufacture or contained varying levels of nonstarter lactic acid bacteria. The level of lipolysis in enzyme-modified cheese was higher than in natural Cheddar cheese; butyrate was the predominant free fatty acid. The addition of exogenous acetate, lactate, and butyrate was also indicated in some enzyme-modified cheeses and may be used to confer a specific flavor characteristic or reduce the pH of the product. Propionate was also found in some enzyme-modified cheese products and most likely originated from Swiss-type cheese used in their manufacture. Propionate is not normally associated with natural Cheddar cheese flavor; however, it may be important in the flavor and aroma of Cheddar enzyme-modified cheese. Levels of lipolysis and glycolysis appear to highly controlled as interbatch variability was generally low. Overall, the production of enzyme-modified Cheddar cheese involves manipulation of the end-products of glycolysis (lactate, propionate, and acetate) and lipolysis to generate products for specific applications.     

A survey of the composition and proteolytic indices of commercial enzyme-modified Cheddar cheese

The compositional and proteolytic parameters in a range of commercial enzyme-modified Cheddar cheeses were quantified, with large variations evident between products from the same manufacturer and from different manufacturers. Analysis of the products indicated the use of cheese of varying fat content, exogenous protein and/or fat, emulsifying salts, flavour potentiators and bulking agents. Extensive proteolysis was a characteristic of these commercial products. Overall, production of enzyme-modified Cheddar cheese involves manipulation of both composition and proteolysis to generate products for specific applications.     

The Use of Viable and Heat-shocked Lactobacillus helveticus DPC 4571 in Enzyme-Modified Cheese Production

The use of viable or attenuated Lactobacillus helveticus DPC 4571 for use in enzyme-modified cheese production was assessed. Optimal heat shocking conditions for attenuation of DPC 4571 were found to be 69°C for 25 sec. Enzyme-modified cheese was produced from an emulsion of pre-hydrolysed rennet curd, water, and butter fat. This substrate was heat-treated and inoculated with either an equivalent level of viable or attenuated cells of DPC 4571 and further incubated under controlled conditions. The heat-treated products produced using attenuated DPC 4571 had a preferred sensory character with strong cheesy savory notes, enhanced secondary proteolysis, and more key volatile flavor compounds than those produced with viable DPC 4571. However, prolonged incubation (>16 h) resulted in growth of advantageous enterococci, which adversely influenced the sensory profile.     

Flavouring reduced fat high fibre cheese products with enzyme modified cheeses (EMCs)

Medium (13%) and low (2%) fat imitation cheeses (pH 6 or 5.5) were flavoured with 5% w/w EMC containing 16%, 28% or 47% total free fatty acids (low to high levels of hydrolysis, respectively) and were examined by a sensory panel. Aroma active short-chain free fatty acids were monitored using gas chromatographic techniques. Regardless of cheese pH or EMC composition, panellists ranked all medium-fat cheeses similarly. Low-fat cheeses flavoured (pH 6 or 5.5) with low or medium lipolysis EMC were described as ‘well-balanced’ and ‘cheesy’ and were significantly more preferred to cheeses containing high hydrolysis EMCs. Low-fat cheeses were least preferred of all cheeses because of ‘very intense’ bursts of off-flavours. Lower pH cheeses were softer and less melting. Higher fat levels in imitation cheese modulated a greater retention of fat-based flavour compounds and improved their release during consumption more than did lower fat levels.     

酶改性干酪的生产技术

目前获得有营养的、经济的和持续的干酪风味产品的方法主要是酶改性干酪(Enzyme Modified Cheese,EMC)。生产EMC所需的技术包括水解干酪/凝乳使用的酶(蛋白酶、肽酶、脂肪酶和酯酶),在可控条件下,水解直到得到所需的风味。EMC的风味最高可达天然干酪风味的30倍,使用这种方法可以生产出许多不同种类的干酪风味产品。主要介绍EMC风味产生的概况,以及生产EMC所需的酶及技术等。     

酶解契达干酪风味形成机理与影响因素

酶解干酪(EMC)相比自然干酪具有更加营养、经济、有效等特点。本文对酶解契达干酪风味产生的机理进行了阐述,并分析了苦味形成的原因;同时综述了生产工艺、商业酶以及微生物对酶解契达干酪风味等影响因素。     

Enzyme-Modified Cheese Technology

Enzyme-modified cheese is derived from cheese by enzymatic means. Enzymes may be added during the manufacture of cheese or after aging. An incubation period under controlled conditions is required for proper flavor development. The mechanism of flavor development in enzyme-modified cheese may be related to the curing of cheese. Although many of the mechanisms for flavor development in cheese are not well understood, carbohydrates, proteins, and fat undergo enzymatic degradation during cheese aging, and these reactions are important in the development of flavor in cheese and enzyme-modified cheese. In some instances, the flavor profile or intensity is proportional to the degree of lipolysis and release of low molecular weight free fatty acids as with Romano or Provolone cheese. In other cases, a similar free fatty acid profile enhances both Cheddar flavor and Swiss cheese flavor but is not characteristic for either.Enzyme-modified cheeses are generally added to foods at levels of .1 to 2.0%, although they can be used at 5% of the formulation to add dairy or cheesy notes to foods and to reduce the requirement for aged cheese in food formulations.     

Lipolysis and free fatty acid catabolism in cheese: a review of current knowledge

The progress of lipolysis and its effect on flavour development during cheese ripening is reviewed. The review begins by describing the structure and composition of milk fat and thereafter discusses current knowledge regarding the role of various lipolytic agents and their influence on lipolysis in various cheese varieties. While free fatty acids (FFA) liberated during lipolysis directly affect cheese flavour, they are also metabolized to other highly flavoured compounds, including methyl ketones and lactones. The pathways of FFA catabolism and the effect of these catabolic products on cheese flavour are discussed. Finally, the current methods for the quantification of FFA in cheese are reviewed and compared.     

Starter strain related effects on the biochemical and sensory properties of Cheddar cheese

A detailed investigation was undertaken to determine the effects of four single starter strains, Lactococcus lactis subsp. lactis 303, Lc. lactis subsp. cremoris HP, Lc. lactis subsp. cremoris AM2, and Lactobacillus helveticus DPC4571 on the proteolytic, lipolytic and sensory characteristics of Cheddar cheese. Cheeses produced using the highly autolytic starters 4571 and AM2 positively impacted on flavour development, whereas cheeses produced from the poorly autolytic starters 303 and HP developed off-flavours. Starter selection impacted significantly on the proteolytic and sensory characteristics of the resulting Cheddar cheeses. It appeared that the autolytic and/or lipolytic properties of starter strains also influenced lipolysis, however lipolysis appeared to be limited due to a possible lack of availability or access to suitable milk fat substrates over ripening. The impact of lipolysis on the sensory characteristics of Cheddar cheese was unclear, possibly due to minimal differences in the extent of lipolysis between the cheeses at the end of ripening. As anticipated seasonal milk supply influenced both proteolysis and lipolysis in Cheddar cheese. The contribution of non-starter lactic acid bacteria towards proteolysis and lipolysis over the first 8 months of Cheddar cheese ripening was negligible.     

Antibotulinal activity of process cheese ingredients

Ingredients used in the manufacture of reduced-fat process cheese products were screened for their ability to inhibit growth of Clostridium botulinum serotypes A and B in media. Reinforced clostridial medium (RCM) supplemented with 0, 0.5, 1, 2, 3, 5, or 10% (wt/vol) of various ingredients, including a carbohydrate-based fat replacer, an enzyme-modified cheese (EMC) derived from a Blue cheese, sweet whey, modified whey protein, or whey protein concentrate, did not inhibit botulinal growth and toxin production when stored at 30 degrees C for 1 week. In contrast, RCM supplemented with 10% soy-based flavor enhancer, 10% Parmesan EMC, or 5 or 10% Cheddar EMC inhibited botulinal toxin production in media for at least 6 weeks of storage at 30 degrees C. Subsequent trials revealed that the antibotulinal effect varied significantly among 13 lots of EMC and that the antimicrobial effect was not correlated with the pH or water activity of the EMC.     

The effect of adding enzyme‐modified cheese on sensory and texture properties of low‐ and high‐fat cream cheeses

The influence of enzyme‐modified cheese (EMC) and fat content on sensory and texture properties of cream cheese was investigated. Enzyme‐modified cheese and fat content were set at three levels each, and organoleptic and texture properties for all experimental cheeses were then determined. Data were analysed using response surface methodology. Both design parameters had significant influence on sensory and texture properties. The EMC did not alter hardness significantly, whereas the higher fat formula had the higher hardness. The results indicated that the optimum level of EMC was less than 1% for high‐fat cream cheeses and at least 5% for low‐fat cream cheeses.     

Evaluation of isolated starter lactic acid bacteria in Ras cheese ripening and flavour development

Eighteen cultures of starter lactic acid bacteria with or without added adjunct cultures, isolated from Egyptian dairy products, were evaluated in experimental Ras cheese for flavour development. Chemical composition of experimental cheeses was within the legal limit for Ras cheese in Egypt. All cultures used in this study had no effect on chemical composition of Ras cheese. Very significant variations in free amino acids, free fatty acids and sensory evaluation have been found among the cultures used in Ras cheesemaking. The levels of free amino acids and free fatty acids were correlated well with flavour development in Ras cheese. Seven of the tested cultures produced acceptable flavour and texture of Ras cheese. The highest overall score of flavour intensity, flavour and texture acceptability were in cheese made using YY47 lactic culture in addition to adjunct culture of Lactobacillus helveticus, Lactobacillus paracasei subsp. paracasei, Lactobacillus delbrueckii subsp. lactis and Enterococcus faecium. This culture can be recommended for Ras cheese manufacture using pasteurized milk.     

Comparison of differences between lexicons for descriptive analysis of Cheddar cheese flavour in Ireland,New Zealand,and the United States of America

Flavour lexicons for cheese provide a way to document cheese flavour for both research and marketing. The objective of this study was to compare differences and similarities in three independently developed sensory languages for Cheddar cheese flavour at three different locations (Ireland, New Zealand, United States of America) using an international selection of Cheddar cheeses. Twelve Cheddar cheeses (four from each country) were evaluated by the three panels using the respective sensory languages. Sensory space patterns obtained by principal component analysis were consistent between the three sites indicating that the overall differentiation of the cheeses by each panel was similar. The key flavour characteristics among the cheeses were described by different attributes. Cheeses were grouped by each site by country of origin suggesting international differences in Cheddar cheese flavour. Cross-cultural differences can exist in sensory language and perception, but highly trained panels using standardized, representative languages can provide comparable results.     

EFFECT OF SOME HERB ESSENTIAL OILS ON LIPOLYSIS IN WHITE CHEESE

The influence of some herb essential oils on the lipolysis of white cheese was examined. The essential oils of Sirmo (wild Allium sp.), thyme (wild Thymus sp.) and mint (wild Mentha sp.) were added individually or in combinations to cheeses. The cheese samples were ripened for 90 days at 5C. Lipolysis rate increased from the beginning to the sixtieth day of ripening, then decreased up to 90 days in cheese samples. The highest lipolysis rate was observed in the control sample while the lowest was in thyme and sirmo-thyme added samples. Differences between cheese samples and ripening periods were found to be statistically significant (P<0.01) in terms of fatty acids production rates. Sirmo and mint essential oils did not affect the lipolysis of white cheese. The sensory acceptability ofsirmo and mint essential oils added cheeses was superior to that of other samples.     

Changes in volatile, sensory and microbial profiles during preparation of smoked ewe cheese

BACKGROUND: Oscypek is a special type of Polish smoked ewe cheese with a unique flavour described as slightly sour, piquant, salted and smoked. In this study the volatile, sensory and microbial profiles of Oscypek cheese were analysed during its various preparation stages of curding, scalding, brining and smoking. RESULTS: The smoked ewe cheese was characterised by 54 volatile compounds belonging to nine different chemical groups (free fatty acids, esters, ketones, alcohols, aldehydes, furans/furanones, phenols, sulfur compounds, terpenes). The sensory aroma profile analysis of unsmoked and smoked cheese showed an important correlation with the analysis of volatile compounds. The microbial profile data indicated that in smoked cheese such as Oscypek the levels of selected bacteria diminished after the curding stage as a result of the subsequent scalding, brining and smoking stages. CONCLUSION: From the results it can be concluded that, although the analysed smoked cheese consisted of three groups of compounds, the first derived from biochemical reactions (free fatty acids, esters, ketones, alcohols, aldehydes, sulfur compounds), the second from smoking (furans and furanones, phenols) and the third from milk flavour (terpenes), it is the smoking process that mainly influences its typical flavour. Copyright © 2011 Society of Chemical Industry     

Influence of fat replacers on chemical composition, proteolysis, texture profiles, meltability and sensory properties of low-fat Kashar cheese

Changes in chemical composition, proteolysis, lipolysis, texture, melting and sensory properties of low-fat Kashar cheese made with three different fat replacers (Simplesse D-100, Avicel Plus CM 2159 or beta-glucan) were investigated throughout ripening. The low-fat cheeses made with fat replacers were compared with full- and low-fat counterparts as controls. Reduction of fat caused increases in moisture and protein contents and decreases in moisture-in-non fat substance and yield values in low-fat cheeses. The use of fat replacers in the manufacture of low-fat Kashar cheese increased water binding capacity and improved overall quality of the cheeses. Use of fat replacer in low-fat cheese making has enhanced cheese proteolysis. All samples underwent lipolysis during ripening and low-fat cheeses with fat replacers had higher level of total free fatty acid than full- or low-fat control cheeses. Texture attributes and meltability significantly increased with addition of fat replacers. Sensory scores showed that the full-fat cheese was awarded best in all stages of ripening and low-fat variant of Kashar cheeses have inferior quality. However, fat replacers except beta-glucan improved the appearance, texture and flavour attributes of low-fat cheeses. When the fat replacers are compared, the low-fat cheese with Avicel Plus CM 2159 was highly acceptable and had sensory attributes closest to full-fat Kashar cheese.