超滤技术在盐水奶酪中的应用研究

以新鲜牛乳为主要原料,结合盐水奶酪的生产工艺,研究了不同超滤膜孔径、操作参数对产品得率和通量的影响,根据实验结果确定最优超滤膜孔径10 nm,操作温度55℃,操作压力0.3 MPa,同时采用L9(33)正交实验方法,研究了不同灭菌方式、混合菌株、盐溶液质量分数对盐水奶酪色泽、滋气味和组织状态的影响,生产盐水奶酪最佳工艺条件是灭菌方式72℃,15 s,混合菌株(乳酸乳杆菌:乳酸乳球菌乳脂亚种)1:1,盐溶液质量分数为15%。     

Influence of the temperature of salt brine on salt uptake by Ragusano cheese

The influence of temperature (12, 15, 18, 21, and 24 degrees C) of saturated brine on salt uptake by 3.8-kg experimental blocks of Ragusano cheese during 24 d of brining was determined. Twenty-six 3.8-kg blocks were made on each of three different days. All blocks were labeled and weighed prior to brining. One block was sampled and analyzed prior to brine salting. Five blocks were placed into each of five different brine tanks at different temperatures. One block was removed from each brine tank after 1, 4, 8, 16, and 24 d of brining, weighed, sampled, and analyzed for salt and moisture content. The weight loss by blocks of cheese after 24 d of brining was higher, with increasing brine temperature, and represented the net effect of moisture loss and salt uptake. The total salt uptake and moisture loss increased with increasing brine temperature. Salt penetrates into cheese through the moisture phase within the pore structure of the cheese. Porosity of the cheese structure and viscosity of the water phase within the pores influenced the rate and extent of salt penetration during 24 d of brining. In a previous study, it was determined that salt uptake at 18 degrees C was faster in 18% brine than in saturated brine due to higher moisture and porosity of the exterior portion of the cheese. In the present study, moisture loss occurred from all cheeses at all temperatures and most of the loss was from the exterior portion of the block during the first 4 d of brining. This loss in moisture would be expected to decrease porosity of the exterior portion and act as a barrier to salt penetration. The moisture loss increased with increasing brine temperature. If this decrease in porosity was the only factor influencing salt uptake, then it would be expected that the cheeses at higher brine temperature would have had lower salt content. However, the opposite was true. Brine temperature must have also impacted the viscosity of the aqueous phase of the cheese. Cheese in lower temperature brine would be expected to have higher viscosity of the aqueous phase and slower salt uptake, even though the cheese at lower brine temperature should have had a more porous structure (favoring faster uptake) than cheese at higher brine temperature. Therefore, changing brine concentration has a greater impact on cheese porosity, while changing brine temperature has a larger impact on viscosity of the aqueous phase of the cheese within the pores in the cheese.     

Evaluation of salt whey as an ingredient in processed cheese

The objective of this research was to determine whether salt whey, obtained from a traditional Cheddar cheese manufacturing process, could be used as an ingredient in processed cheese. Due to its high salinity level, salt whey is underutilized and leads to disposal costs. Consequently, alternative uses need to be pursued. The major components of salt whey (salt and water) are used as ingredients in processed cheese. Three replicates of pasteurized processed cheese (PC), pasteurized processed cheese food (PCF), and pasteurized processed cheese spread (PCS) were manufactured. Additionally, within each type of processed cheese, a control formula (CF) and a salt whey formula (SW) were produced. For SW, the salt and water in the CF were replaced with salt whey. The composition, functionality, and sensory properties of the CF and SW treatments were compared within each type of processed cheese. Mean melt diameter obtained for the CF and SW processed cheeses were 48.5 and 49.4 mm, respectively, for PC, and they were 61.6 and 63 mm, respectively, for PCF. Tube-melt results for PCS was 75.1 and 79.8 mm for CF and SW treatments, respectively. The mean texture profile analysis (TPA) hardness values obtained, respectively, for the CF and SW treatments were 126 N and 115 N for PC, 62 N and 60 N for PCF, and 12 N and 12 N for PCS. There were no significant differences in composition or functionality between the CF and SW within each variety of processed cheese. Consequently, salt whey can be used as an ingredient in PC without adversely affecting processed cheese quality.     

Reduced‐sodium cheeses: Implications of reducing sodium chloride on cheese quality and safety

Sodium chloride (NaCl) universally well‐known as table salt is an ancient food additive, which is broadly used to increase the storage stability and the palatability of foods. Though, in recent decades, use of table salt in foods is a major concern among the health agencies of the world owing to ill effects of sodium (Na) that are mostly linked to hypertension and cardiovascular diseases. As a result, food scientists are working to decrease the sodium content in food either by decreasing the rate of NaCl addition or by partial or full replacement of NaCl with other suitable salts like potassium chloride (KCl), calcium chloride (CaCl₂), or magnesium chloride (MgCl₂). However, in cheese, salt reduction is difficult to accomplish owing to its multifaceted role in cheese making. Considering the significant contribution in dietary salt intake (DSI) from cheese, researchers across the globe are exploring various technical interventions to develop reduced‐sodium cheeses (RSCs) without jeopardizing the quality and safety of cheeses. Thus, the purpose of this study is to provide an insight of NaCl reduction on sensory, physicochemical, and technofunctional attributes of RSCs with an aim to explore various strategies for salt reduction without affecting the cheese quality and safety. The relationship between salt reduction and survival of pathogenic and spoilage‐causing microorganisms and growth of RSCs microflora is also discussed. Based on the understanding of conceptual and applied information on the complex changes that occur in the development of RSCs, the quality and safety of RSCs can be accomplished effectively in order to reduce the DSI from cheese.     

Texture,flavor, and sensory quality of buffalo milk Cheddar cheese as influenced by reducing sodium salt content

The adverse health effects of dietary sodium demand the production of cheese with reduced salt content. The study was aimed to assess the effect of reducing the level of sodium chloride on the texture, flavor, and sensory qualities of Cheddar cheese. Cheddar cheese was manufactured from buffalo milk standardized at 4% fat level by adding sodium chloride at 2.5, 2.0, 1.5, 1.0, and 0.5% (wt/wt of the curd obtained). Cheese samples were ripened at 6 to 8°C for 180 d and analyzed for chemical composition after 1 wk; for texture and proteolysis after 1, 60, 120, and 180 d; and for volatile flavor compounds and sensory quality after 180 d of ripening. Decreasing the salt level significantly reduced the salt-in-moisture and pH and increased the moisture-in-nonfat-substances and water activity. Cheese hardness, toughness, and crumbliness decreased but proteolysis increased considerably on reducing the sodium content and during cheese ripening. Lowering the salt levels appreciably enhanced the concentration of volatile compounds associated with flavor but negatively affected the sensory perception. We concluded that salt level in cheese can be successfully reduced to a great extent if proteolysis and development of off-flavors resulted by the growth of starter and nonstarter bacteria can be controlled.     

The effect of salt concentration on rancidity in Gaziantep cheese

Gaziantep cheese is a non‐fermented and enzyme clotted type cheese. The changes in oxidative and hydrolytic rancidity in the cheese were analysed during its storage. Storage conditions were selected as 4, 10 and 20°C and 90, 170, 200 and 230 g kg⁻¹ salt solutions by considering the traditional storage conditions. Oxidative rancidity increased with increasing temperature and NaCl concentration in the brine. Hydrolytic rancidity increased with increasing temperature and decreasing salt content of the cheese. The extent of oxidative rancidity was found to be higher than hydrolytic rancidity. The results of this study showed that the storage temperature should not be higher than 10°C and brine concentration must be higher than 90 g kg⁻¹ and lower than 230 g kg⁻¹ to minimize lipid oxidation. Gaziantep cheese was organoleptically examined after 2 months of storage at 20°C and in 90, 170 and 230 g kg⁻¹ salt solutions, and it was found that even at a peroxide value around 1 meq kg⁻¹, acceptable levels of changes in flavour were observed. Sensory analysis results showed that textural properties of Gaziantep cheese changed with salt concentration of the brine. © 1999 Society of Chemical Industry     

乳化盐对干酪粉物理化学特性的影响

研究了焦磷酸钠、磷酸氢二钠、柠檬酸钠、三聚磷酸钠及它们的复合盐（磷酸氢二钠＋柠檬酸钠、三聚磷酸钠＋柠檬酸钠）对喷雾前干酪浆的表观黏度、pH值、可溶性氮含量；干酪粉的容重、溶解度、水分含量、游离脂肪酸含量、感官评价等物理化学特性的影响。结果表明，添加不同的乳化盐对干酪粉的水分含量、游离脂肪酸含量有显著影响（p〈0．05），添加量（2％-4％之间）对干酪粉的水分含量影响显著（P〈0．05）。当三聚磷酸钠与柠檬酸钠比为1：1，添加量为原料干酪的3．0％左右时，干酪粉有较好的物理化学特性，而且感官评分最高。     

Modelling average concentrations of salt and salt substitute in partial or total volumes of semihard cylindrical cheeses

Average concentrations of NaCl and KCl (as salt substitute) in a cylindrical Fynbo cheese during salting and ripening stages were analytically modelled for partial and total volumes. The results obtained using the novel analytical solutions were compared with those obtained by numerical modelling solutions considering the computing central processing unit (CPU) time necessary for similar error values for each method. The CPU time was reduced when the analytical solutions were used to obtain concentrations with the same significant figures. The equations obtained could probably be used to study solute diffusion in other similar solid foodstuffs. The advantages of analytical solutions are: a short CPU time is required and these solutions can be used to predict parameters by regression of experimental data more easily.     

Reduction of salt (NaCl) losses during the manufacture of cheddar cheese

The objective of this study was to evaluate the effects of cheese-making technologies, including homogenization of cream, ultrafiltration, and vacuum condensing of milk, on the retention of salt in Cheddar cheese. One part of pasteurized, separated milk (0.58% fat) was ultrafiltered (55 degrees C, 16.0% protein), another vacuum condensed (12.5% protein), and the third was not concentrated. Cheddar cheese was manufactured using 6 treatments by standardizing unconcentrated milk to a casein-to-fat ratio of 0.74 with unhomogenized 35% fat cream (C), homogenized (6.9 MPa/3.5 MPa) 35% fat cream (CH), ultrafiltered milk and unhomogenized cream (UF), ultrafiltered milk and homogenized cream (UFH), condensed milk and unhomogenized cream (CM), and condensed milk and homogenized cream (CMH). Treatments C and CH had 3.7% fat and 3.5% protein, and the respective values for the remaining treatments were 4.9 and 4.6. The milled curd was dry salted at 2.7% by weight. The salt content of the cheeses receiving homogenization treatment was higher at 1.83 and 1.70% for CH and UFH, respectively, compared with their corresponding controls at 1.33%. The salt content in cheeses from CMH was 1.64% and was not affected by homogenization. Salt retention in C increased from 41.7 to 59.2% in CH, and in UF it increased from 42.5 to 54.5% in UFH. There was a corresponding decrease in the salt content of whey from these cheeses.     

Interaction of brine concentration, brine temperature, and presalting on salt penetration in Ragusano cheese

Thirty-one 3.6-kg blocks of Ragusano cheese were made on each of 6 different days (in different weeks) starting with a different batch of milk on each day. On d 1, 3, and 5, the cheeses were not presalted and on d 2, 4, and 6, all cheeses were presalted (PS). One of the 31 blocks of cheese was selected at random for analysis before brine salting (i.e., on d 0). The remaining 30 blocks were randomly divided into 2 groups of 15 blocks each; one group was placed in 18% brine (18%B) and the other group was placed in saturated brine (SB). For the 15 blocks within each of the 2 brine concentrations (BC), 5 blocks were placed in a brine tank at 12° C, 5 at 15° C, and 5 at 18° C, and submerged for 24 d. The research objective was to determine the combined impacts (i.e., interactions) of PS the curd before stretching, BC (SB vs. 18%B), and brine temperature (BT; 12, 15, and 18° C) on salt uptake, moisture content, and yield of Ragusano cheese. Although BC, BT, and PS each had their own separate impacts on salt uptake, there was little interaction of these effects on salt uptake when they were used in combination. The PS most quickly delivered salt to the interior of the cheese and was the most effective approach to salting for controlling early gas formation. There were strong separate impacts of BC, BT, and PS on cheese moisture content, moisture loss, and net weight loss, with BC having the largest separate impact on these parameters. Reducing BT reduced salt content and increased moisture, but the effects were small. The more important effect of reduced BT was to reduce growth of gas forming bacteria. The 18%B produced higher moisture, and less moisture and weight loss than SB. The effect of interactions of BC, BT, and PS on moisture loss and net weight loss were small. To achieve the maximum benefit from the various approaches to salting for controlling early gas formation in Ragusano cheese, PS combined with slightly lower BT (i.e., 15° C instead of 18° C) should be used. Although using 18%B instead of SB did increase salt uptake, the point at which improved salt uptake occurred due to use of 18%B did not provide benefit in prevention of early gas formation, as reported separately. However, use of 18%B instead of SB provided a 9.98% increase in cheese yield due to reduced moisture loss during brining; this would be very attractive to cheese makers. The increase in yield needs to be balanced against the risk of growth of undesirable bacteria in the 18%B and the creation of another cheese quality defect.     

Short communication: Little change takes place in Camembert-type cheese water activities throughout ripening in terms of relative humidity and salt

Water activity (a_w) affects the growth and activity of ripening microorganisms. Moreover, it is generally accepted that a_w depends on relative humidity (RH) and salt content; these 3 variables were usually measured on a given day in a cheese without the microorganism layer and without accounting for a distinction between the rind, the underrind, and the core. However, a_w dynamics have never been thoroughly studied throughout cheese ripening. Experimental Camembert cheeses were ripened under controlled and aseptic conditions (temperature, gaseous atmosphere, and RH) for 14 d. In this study, only RH was varied. Samples were taken from the cheese (microorganism layer)–air interface, the rind, and the core. The a_w of the cheese–air interface did not change over ripening when RH varied between 91 and 92% or between 97 and 98%. However, on d 5, we observed a small but significant increase in a_w, which coincided with the beginning of growth of Penicillium camemberti mycelia. After d 3, no significant differences were found between the a_w of the cheese–air interface, the rind, and the core. From d 0 to 3, cheese rind a_w increased from 0.94 to 0.97, which was probably due to the diffusion of salt from the rind to the core: NaCl content in the rind decreased from 3.7 to 1.6% and NaCl content in the core increased from 0.0 to 1.6%. Nevertheless, a_w did not significantly vary in the core, raising questions about the real effect of salt on a_w.     

Mozzarella干酪提取液的抗菌活性

Mozzarella干酪中酪蛋白抗菌肽对人体有非常重要的作用。为了研究酪蛋白提取液的抑菌作用,对成熟期为40 d、50 d和60 d的Mozzarella干酪,分别用无菌蒸馏水、醋酸-醋酸钠缓冲溶液和TCA提取法制备干酪提取液,探讨了干酪提取液对大肠杆菌、枯草芽孢杆菌、酵母菌和黑曲霉的抑制作用。结果显示,不同成熟期Mozzarella干酪的提取液对大肠杆菌、枯草芽孢杆菌和酵母菌均有一定的抑制作用。成熟期为40 d的Mozzarella干酪,用无菌蒸馏水提取出的提取液对大肠杆菌的抑菌性最强;成熟期为60 d的Mozzarella干酪,用TCA提取法提取出的提取液对枯草芽孢杆菌、酵母菌和黑曲霉的抑菌性最强。     

The influence of sweeteners in probiotic Petit Suisse cheese in concentrations equivalent to that of sucrose

As in the case of probiotic functional foods in recent years, demand has increased notably for light or diet foods with added sweeteners. However, little is known about the effect of different sweeteners on the microorganisms present. Thus, the objective of the current study was to establish the ideal sucrose concentration and equivalent concentrations of different sweeteners and to determine, by microbiological analyses, the influence of these compounds on the viability of the starter and probiotic cultures used in the production of strawberry-flavored Petit Suisse cheese during its shelf life. The ideal sucrose concentration was determined using the just-about-right (JAR) scale, and the equivalent concentrations of the sweeteners were subsequently determined by the magnitude estimation method. Microbiological analyses were also carried out to check the viability of the cultures during the product’s shelf life. The results showed that the compounds Neotame (NutraSweet, Chicago, IL) and stevia presented, respectively, the greatest and least sweetening power of the sweeteners tested. None of the sweeteners used in this study exerted a negative effect on the viability of the starter or probiotic cultures, and thus we were able to obtain a probiotic, functional food with reduced calorie content.     

Calcium lactate as an attractive compound to partly replace salt in blue-veined cheese

In addition to their high sodium content, cheeses are thought to induce an acid load to the body, which is associated with deleterious effects on consumers' health. Our objective was to explore the use of alkalinizing salts in partial substitution of NaCl to reduce both the sodium content and the acid-forming potential of cheese, without altering its sensory properties. Blue-veined cheeses were produced under industrial conditions, using brine salting followed by dry salting with a 4:1 (wt/wt) mixture of calcium lactate:NaCl or calcium citrate:NaCl. Sodium chloride was used in 2 granulometries: coarse (control treatment) and fine, to obtain homogeneous mixtures with the organic salts. Cheeses were then ripened for 56 d. No major appearance defects were observed during ripening. Calcium lactate substitution decreased the Na content of the cheese core by 33%, and calcium citrate substitution increased the citrate content of the cheese core by 410%, respectively, compared with fine NaCl. This study highlighted the substantial role of salt granulometry in sodium content, with the use of the coarse salt reducing the sodium content by 21% compared with fine salt. Sensory profiles showed nonsignificant differences in bitter and salty perceptions of salt-substituted cheeses with calcium lactate and calcium citrate compared with control cheeses. The use of calcium lactate should be considered to reduce the sodium content and improve the nutritional quality of cheeses while maintaining the sensory quality of the products. Alkalinizing organic salts could replace the acidifying salts KCl or CaCl₂, which are currently used in salt replacement and are not recommended for consumers with renal disease. The method described here should be considered by cheese-making producers to improve the nutritional quality of cheese. Additional nutritional optimization strategies are suggested.     

A fast micromethod for the estimation of nisin activity in a soft cheese

The British Standard protocol currently used to determine the nisin concentration in cheese requires the manipulation of a 40 g sample involves two critical points, pH adjustment and heating/cooling. In this work, we developed a fast micromethod that permits the manipulation of 0.2 g cheese, substitutes the use of 0.02N HCl by 50 mM citric acid and facilitates the handling of many samples in reduced time, and with increased efficiency/yield. This change keeps the pH stable at ~3.4, enough to sidestep the pH adjustment, and nisin antimicrobial activity was stable at boiling temperatures.     

From undefined red smear cheese consortia to minimal model communities both exhibiting similar anti-listerial activity on a cheese-like matrix

Starting from one undefined cheese smear consortium exhibiting anti-listerial activity (signal) at 15 °C, 50 yeasts and 39 bacteria were identified by partial rDNA sequencing. Construction of microbial communities was done either by addition or by erosion approach with the aim to obtain minimal communities having similar signal to that of the initial smear. The signal of these microbial communities was monitored in cheese microcosm for 14 days under ripening conditions. In the addition scheme, strains having significant signals were mixed step by step. Five-member communities, obtained by addition of a Gram negative bacterium to two yeasts and two Gram positive bacteria, enhanced the signal dramatically contrary to six-member communities including two Gram negative bacteria. In the erosion approach, a progressive reduction of 89 initial strains was performed. While intermediate communities (89, 44 and 22 members) exhibited a lower signal than initial smear consortium, eleven- and six-member communities gave a signal almost as efficient. It was noteworthy that the final minimal model communities obtained by erosion and addition approaches both had anti-listerial activity while consisting of different strains. In conclusion, some minimal model communities can have higher anti-listerial effectiveness than individual strains or the initial 89 micro-organisms from smear. Thus, microbial interactions are involved in the production and modulation of anti-listerial signals in cheese surface communities.     

Influence of presalting and brine concentration on salt uptake by Ragusano cheese

The impact of presalting and nonsaturated brine on salt uptake by Ragusano cheese was determined. The study included four treatments: 1) the traditional method using no presalting and saturated brine, 2) presalting and saturated brine, 3) no presalting and 18% brine for 8 d followed by 16 d in saturated brine, and 4) presalting and 18% brine for 8 d followed by 16 d in saturated brine. Cheese blocks were weighed and sampled before brine salting (time 0) and after 1, 4, 8, 16, and 24 d of brining for each treatment. Presalting delivered 60% of the normal level of salt in the center of the block prior to brine salting without decreasing the rate of uptake of salt from either saturated or 18% brine. Use of 18% salt brine for the first 8 d of 24 d of brine salting increased the rate of salt uptake, compared with 24 d in saturated brine. The increased rate of salt uptake with 18% brine compared with saturated brine was related to the impact of salt brine on the moisture content and porosity of the cheese near the surface of the block. Brine with higher salt content causes a rapid loss of moisture from cheese near the surface of the block. Moisture loss causes shrinkage of the cheese structure and decreases porosity, which impedes moisture movement out and salt movement into the block. The use of 18% salt brine for the first 8 d delayed the moisture loss and cheese shrinkage at the exterior of the block and allowed more salt penetration.     

Technical note: High-throughput method for antifungal activity screening in a cheese-mimicking model

In this study, we developed a high-throughput antifungal activity screening method using a cheese-mimicking matrix distributed in 24-well plates. This method allowed rapid screening of a large variety of antifungal agent candidates: bacterial fermented ingredients, bacterial isolates, and preservatives. Using the proposed method, we characterized the antifungal activity of 44 lactic acid bacteria (LAB) fermented milk-based ingredients and 23 LAB isolates used as protective cultures against 4 fungal targets (Mucor racemosus, Penicillium commune, Galactomyces geotrichum, and Yarrowia lipolytica). We also used this method to determine the minimum inhibitory concentration of a preservative, natamycin, against 9 fungal targets. The results underlined the strain-dependency of LAB antifungal activity, the strong effect of fermentation substrate on this activity, and the effect of the screening medium on natamycin minimum inhibitory concentration. Our method could achieved a screening rate of 1,600 assays per week and can be implemented to evaluate antifungal activity of microorganisms, fermentation products, or purified compounds compatible with dairy technology.     

Proteolysis and textural properties of low‐fat ultrafiltered Feta cheese as influenced by maltodextrin

Maltodextrin was used as a fat replacer in low‐fat ultrafiltered cheese. Fat was replaced with 25% maltodextrin milk solution (w/w) in cheese at 15 and 50% (w/w). The chemical, rheological and sensory properties as well as the microstructure of the cheese samples were evaluated after storage for 2 months at 8 °C. Maltodextrin affected the chemical (pH, dry matter, fat, water‐soluble nitrogen to total nitrogen, nonprotein nitrogen to total nitrogen, total free amino acid) and rheological (mean relaxation time) properties, as well as the microstructure. In general, based on textural properties, sensory evaluation and economic aspects, the 50%‐fat‐reduced sample was selected as the best treatment.     

Growth of Lactobacillus paracasei ATCC 334 in a cheese model system: a biochemical approach

Growth of Lactobacillus paracasei ATCC 334, in a cheese-ripening model system based upon a medium prepared from ripening Cheddar cheese extract (CCE) was evaluated. Lactobacillus paracasei ATCC 334 grows in CCE made from cheese ripened for 2 (2mCCE), 6 (6mCCE), and 8 (8mCCE) mo, to final cell densities of 5.9 × 10⁸, 1.2 × 10⁸, and 2.1 × 10⁷ cfu/mL, respectively. Biochemical analysis and mass balance equations were used to determine substrate consumption patterns and products formed in 2mCCE. The products formed included formate, acetate, and d-lactate. These data allowed us to identify the pathways likely used and to initiate metabolic flux analysis. The production of volatiles during growth of Lb. paracasei ATCC 334 in 8mCCE was monitored to evaluate the metabolic pathways utilized by Lb. paracasei during the later stages of ripening Cheddar cheese. The 2 volatiles detected at high levels were ethanol and acetate. The remaining detected volatiles are present in significantly lower amounts and likely result from amino acid, pyruvate, and acetyl-coenzyme A metabolism. Carbon balance of galactose, lactose, citrate, and phosphoserine/phosphoserine-containing peptides in terms of d-lactate, acetate, and formate are in agreement with the amounts of substrates observed in 2mCCE; however, this was not the case for 6mCCE and 8mCCE, suggesting that additional energy sources are utilized during growth of Lb. paracasei ATCC 334 in these CCE. This study provides valuable information on the biochemistry and physiology of Lb. paracasei ATCC 334 in ripening cheese.