Abstract: Nowadays, there is growing awareness about reduced fat food as well as free fat products. Low fat milk products, particularly low fat cheese represents a good choice for the development of new products with functional properties. Consumers are always looking forward to desirable and healthy products. Therefore, consumer’s demand for low-fat/calorie products has significantly raised in an attempt to limit health problems, to lose or stabilize their weight and to work within the frame of a healthier diet. Low fat cheese often suffers from undesirable flavor and texture. So, for these reasons, there are many strategies to overcome these defects with the using of additives such as stabilizers and fat replacers. Another solution is using exo-polysaccharide which produced from lactic acid bacteria (EPS-producing cultures) to improve functional low fat cheese product. Several studies highlighted the positive effect of EPS-producing cultures on the physical and functional properties of reduced fat Cheddar cheese. The objective of this review is to establish low fat cheese, their characteristics and technological it’s manufacturing.
INTRODUCTION
The amount and type of fat consumed is important to the etiology of several chronic disease such as obesity, cardiovascular disease and cancer. As a result, consumers more readily adhere to nutritional guidelines concerning fat consumption (Katsiari et al., 2002a; Kucukoner and Haque, 2006). This association has created an increased awareness and a dramatic increase in the demand and supply for low-fat foods including cheese varieties (Katsiari et al., 2002b).
Recently a worldwide tendency for the consumption of low-fat foods has been observed in a variety of countries, due to public concern about the excess ingestion of calories and fats, leading to an increase in the consumption of diet and light foods (Oliveira and Assumpcio, 2000). Dairy processors have also taken noted of this tendency, which it reflects in development of and sensorial evaluation of several low fat cheeses (Nelson and Barbano, 2004; Koca and Metin, 2004; Madadlou et al., 2005; Kilcawley et al., 2007).
As El Soda (2014) mentioned that difficulties arise when attempts are made to produce low fat variants of cheeses that are popular and established in the market as full fat varieties. In producing low fat variants of standard fat cheeses such as Cheddar, processing parameters must be altered substantially in order to produce an acceptable texture and flavor. So, different strategies were described to overcome both texture and flavor defects, which include the retention of higher moisture in the curd, which can partially replace fat and improve texture through cutting into larger cubes, lowering the cooking temperature draining and milling at a higher pH. Stabilizers and fat replacers were also used to improve texture. This practice was often followed by off flavor development.
However, low-fat cheeses, that exhibit the characteristics of conventional full-fat cheeses are needed for consumer markets. Cheese with reduced fat content may exhibit dilute flavor and poor texture For this reason, many research development around the world have contributed to improvements in the quality of low-fat cheeses, many patents have been issued worldwide involving the manufacture of low-fat cheeses. The major objective in developing these procedures is to produce low fat cheeses that are similar in characteristics to their full-fat counter parts (Drake et al., 1999).
Consequently, exo-polysaccharides-producing lactic acid bacteria (EPS-producing cultures) have been used to improve product functionality in the dairy industry by binding free water. They have been suggested for low fat Cheddar cheese making for several reasons. They have the ability to bind water and to increase moisture, exo-polysaccharides increase moisture retention by water binding or entrapment within their 3-dimensional network. In addition, EPS seem to act as nuclei for the formation of large pores in cheese, they also increase the viscosity of the aqueous phase in cheese and modify its flow characteristics. In addition, EPS interfere with protein-protein interactions physically or through their interaction with proteins (El Soda, 2014).
On the other hand, EPS produced by starter cultures are hetero polysaccharides. Perry et al. (1997) found that EPS-producing Streptococcus thermophilus could increase moisture retention in low-fat Mozzarella cheese. The EPS were responsible for the water-binding properties of this bacterium in cheese (Low et al., 1998). It was also confirmed that encapsulated and ropy EPS-producing S. thermophilus strains can be utilized to increase the moisture level of cheese. However, only the encapsulated EPS can improve these properties without adversely affecting whey viscosity (Broadbent et al., 2001; Petersen et al., 2000). Some other EPS-producing strains, for example, Lactococcus lactis spp. cremoris also could contribute to the modification of cheese texture, microstructure (Dabour et al., 2006) and melting properties (Awad et al., 2005). These and similar researches devoted their efforts to low fat cheeses because such cheeses tend to become tough, rubbery and have poor stretching properties (Mistry and Anderson, 1993).
FUNCTIONAL ROLE OF DIETARY FAT
Dietary fats is a major energy source is essential for growth and development and provides essential fatty acids needed for maintaining structure of cell membrane and for prostaglandin synthesis. In addition, fat aid in the absorption of fat-soluble vitamins and other phyto-chemicals. Fat is a multifunctional constituent in food as it plays an essential role in flavor, texture and color. Fat flavor consists of a large number of constituents. The main compounds are short chain fatty acids and their esters, Y and б-lactones, ketones and aldehydes (Kinsella, 1975). Fat in food has multiple functions during cooking processes. Its heat transfer enable rapid heating and attainment of very high temperatures. Fat absorbs many flavor compounds and rounds the flavor by reducing the sharpness of acid ingredients. Also, the structure of food and its composition play a dominant role in flavor perception. The basic edible sensations of fat-containing foods are viscosity (thickness, body and fullness), lubricity (creaminess, smoothness), absorption/adsorption and other factors such as cohesiveness (Sandrou and Arvanitoyannis, 2000).
Functionally, fats affect the melting points, viscosity and body, crystallinity and spreadability of many foods (Drewnowski, 1998). Fat impacts a velvety mouth feel to products such as ice creams, desserts and cream soups. Smoothness in ice creams and some cadies is due to fat preventing the formation of large water or sugar crystals. Fat removal from cheeses results in a pasty curd or a rubbery texture. Low fat puddings, salad dressing, soups and dairy products are watery without the addition of fat extenders or mimics. Fats are responsible for the aroma and texture of many foods, thereby affecting the overall palatability of the diet. Although fat in food may increase acceptance, high fat foods and diets are also high in calories (Jonnalagadda, 2005), which may be problematic for the majority of individuals struggling with energy balance.
CHARACTERISTICS OF LOW FAT CHEESE
Low-fat cheeses are considered to be less acceptable to consumers than their full-fat counterparts due to texture, functional properties and flavor defects.
Flavor: The lack of flavor in low-fat cheese may be due to the lack of precursors from the fat, the lack of fat as a solvent for flavor compounds or differences in the physical structure of low-fat cheese that inhibits certain enzymic reactions essential for the formation of flavor compounds (Urbach, 1997). Fatty acids in cheese originate mostly from lipolysis of the milk fat. Several studies have identified. Deficiencies in butanoic and hexanoic acids in low-fat cheeses (Banks et al., 1998; Dimos et al., 1996) whets in full. Fat cheddar optimum levels of these compounds are critical to the intensity of cheddar flavor (Barlow et al., 1989). In a comparison of volatiles from full and reduced fat cheddar, Dimos et al. (1996) found that the concentration of methane thiol in cheese was highly correlated with flavor grade, which suggested that the lack of flavor in reduced-fat cheddar was due mainly to the lack of methane thiol.
Deficiency in milk fat-derived flavor compounds including short to medium-chain-carboxylic acids, methyl ketones and 8 and σ lactones has been associated with poor flavor development in a 50% fat-reduced cheddar (Wijesunda and Watkins, 2000).
Bitter peptides are formed by the action of various proteinases on the Caseins. Bitterness occurs in cheese when these peptides accumulate to an excessive concentration as a result of either overproduction or inadeyuate degardation by microbial peptidases. Although, bitter peptidase can orginate from α s1 or B casein, it is action of chymosin and/or the lactococcal cell envelope proteinase on the hydrophobic c-terminal region of B-casein that is mainly associated with production of bitter peptides (McSweeney, 1997). Reduced partititioning of hydorphobic bitter peptides in the fat phase of low-fat cheeses may be the causative factor in increasing the susceptibility of low-fat cheeses to bitter off-flavors (McSweeney, 1997).
Development of bitterness can be minimized by increasing salt-in-moisture (Banks et al., 1993; Mistry and Kasperson, 1998) but this can inhibit proteolysis and increase the firmness of the cheese (Mistry and Kasperson, 1998). While it is generally accepted that bitterness in cheese results from the accumulation of an abnormally high concentration of hydrophobic peptides other compounds such as some amino acids, amides, long-chain ketones and some monolgy cerdies may contribute (McSweeney, 1997).
Texture and functionality: Textural defects include increasing firmness, rubberness, hardness, dryness and graininess (Olson and Johnosn, 1990) fat has a major effect on the microstructrue, texture and functionality of cheddar cheese (Guinee et al., 2000).
Texture development in cheese occurs due to the breakdown of αs1 Casien during ripening (Lawrence et al., 1987). Furthermore, milk fat normally provides atypifcal smoothness to a full fat cheese by being evenly distributed within the casein matrix of cheese. When fat is removed, as in low fat cheeses, casein plays a greater role in texture development (Fig. 1). In low fat variants there is in adequate breakdown of casein and therefore, the cheese appears to have relatively firm texture. The extent of hydrolysis depends on the moisture and salt content of the cheese (Mistry and Kasperson, 1998). Higher pH of whey at draining and lower cook temperatures normally employed in low fat cheese manufacture lead to a lower retention to chymosin in cheese and lower plasmin activity. This is also partly the reason for a lower extent of protein breakdown during ripening. Another outcome of these manufacturing conditions is the relatively higher level of calcium retention in cheese, which imparts firmness to cheese (Nauth and Ruffie, 1995).
| Fig. 1: | Scanning electron micrographs of (a) Full fat and (b) Low fat Cheddar cheese. Full fat cheese has a more open structure than low fat cheese |
Reduction in fat content resulted in increases in the apparent viscosity and melt time and a decrease in the flow ability of the baked cheese at most ripening times throughout a 180 day ripening period. Changes in the rheology and functionality were attributed to the decrease in the quantity of free oil released on cooking and the increases in the content of intact para-casein and the volume fraction of the casein matrix associated with the reduction in fat content.
Studies and cheddar found no association between the breakdowns of αs1-casein and melt but degradation of B-Casein correlated with increased melting of the cheese (Bogenrief and Olson, 1995). Shakeel-Ur-Rehman et al. (2003) suggested that meltability is influenced by continued hydrolysis of α s1 and B-casien into small peptides rather than by the initial hydrolysis of intact proteins. These studies suggest that degradation patterns of cheese proteins, particularly αs1-casein may vary and thereby play an important role in functionality.
Difficulties in melting low or reduced-fat shredded mozzarella can be overcome by lightly coating the cheese shred surface with a small amount oil to prevent surface dehydration (Rudan and Barbono, 1998). A barrier to block moisture loss using a thin hydrophobic surface coating on the shred produces excellent melting and browning of fat-free and low-fat mozzarella cheese during pizza baking (McMahon and Oberg, 1998; Rudan and Barbono, 1998).
Though Mozzarella cheese is not considered a ripened cheese, a small degree of casein breakdown is required for body and texture development and functionality. For example, when fat content was reduced to below 15% proteolysis during storage decreased and the hardness of cheese increased, which in turn also adversely affected its functionality (Rudan et al., 1999).
Yield of cheese: The composition of milk for manufacturing low fat cheeses differs markedly from that of full fat cheeses in a number of ways. The total fat content of milk is obviously lower, therefore, the percentage total protein in milk is slightly higher. The net result is lower total solids in the milk. The ratio of casein to fat will also be much higher in milk for low fat cheese making. While it is true that fat in cheese is replaced by moisture, the total yield of cheese (kg cheese per kg milk) is lower for low fat cheeses because the total amount of fat removed is not equal to the amount of moisture added. Rudan et al. (1999) demonstrated that the yield of Mozzarella cheese of 5% fat was 30% lower than that of a cheese of 25% fat.
Fat and nitrogen recoveries in cheese are also important in cheese yield. The percentages of expected recoveries depend on variety and are affected by a number of cheese making factors. For Mozzarella fat recovery is 85% (Rudan et al., 1999) and Cheddar it is 93% (Kosikowski and Mistry, 1997). Nitrogen recoveries for many hard cheeses are near 75%. Nitrogen recoveries for low fat cheese making are not affected to the same degree as fat. As the targeted fat content of cheese is lowered, the percentage fat recovered in cheese is lowered and may be controlled partly by adjusting the casein to fat ratio in milk. At optimum rennet curd firmness at cutting, fines losses and hence fat losses are reduced.
TECHNOLOGY OF LOW FAT CHEESE MANUFACTURING
Procedures developed for manufacturing low fat cheeses involve three broad approaches that include (a) Processing techniques, (b) Adjunct cultures, (c) Use of additives such as fat replacers and (d) novel fat removed method. Combinations of these procedures are also used.
Processing techniques: The fat content of milk used for manufacturing low fat cheeses depends on the desired fat content in the cheese and generally ranges from 0.5 to approximately 1.8%. Milk may be fortified with nonfat dry milk or may be condensed to up to 1.8 (Anderson et al., 1993), directly ultra-filtered (McGregor and White, 1990) or fortified with dried ultra-filtered or micro-filtered retentate (St-Gelais et al., 1998). Rodriguez et al. (1999) concluded that semi-hard low fat cheeses made with milk concentrated by microfiltration had sensory qualities similar to full fat counterparts because of the retention of less (35%) whey proteins.
The ratio of casein to fat in milk is also important. For manufacturing a 33% fat reduced Cheddar cheese a ratio of 1.58 is desirable (Kosikowski and Mistry, 1997), whereas for Mozzarella cheese with 50% fat reduction a ratio of 2.4 was suggested (Merrill et al., 1994).
Other primary cheese making parameters that may be manipulated include temperature of cooking, time of holding during cooking, pH at milling and rate of salting (Johnson and Chen, 1995).
The general goal is to replace fat in cheese with moisture without adversely affecting cheese yield and quality. This is accomplished in part by lowering cooking temperatures. In low fat Cheddar cheese making the cook temperature is 30-351°C, depending on the moisture content desired (Banks et al., 1989). Further moisture retention is attained by employing a high pH at mill (Kosikowski and Mistry, 1997). For low fat Cheddar this pH may range between 5.6 and 5.8. Washing curd with cold water (221°C) also helps retain moisture, remove excess lactose and solubilize calcium, which helps soften cheese texture. This step helps in preventing excessive acid development during aging.
Disadvantages include the loss of cheese flavor compounds, resulting in a cheese with a bland flavor and the development of off flavors during ripening such as meaty-brothy and unclean (Johnson et al., 1995). Chen and Johnson (1996) have addressed these effects. The procedure involves the cutting of rennet curd when very firm, high pH at drain (6.45) and high pH at mill (5.9). By eliminating curd washing, an increased retention of calcium phosphate retention increases buffering capacity and restricts the development of an excessively low pH. Excessive calcium, on the other hand, adversely affects functional properties of cheeses such as Mozzarella. Nauth and Hayashi (1995) suggest lowering the pH of milk by adding rehydrated cultured skim milk. This lowers the pH of milk and converts colloidal calcium to the soluble form, which is eventually removed into the whey during drainage.
Other methods to increase moisture retention include the inclusion of whey proteins and sweet buttermilk in cheese. Whey proteins denatured by high heat treatment (>801°C) have increased water absorption capacity and have been used in the manufacture of reduced fat Havarti-type cheese (Lo and Bastian, 1998) and low fat Edam cheese (Schreiber et al., 1998). Excessive whey protein addition is likely to interfere with rennet curd formation and ultimately adversely affect cheese quality (Guinee et al., 1998). Schreiber et al. (1998) suggested use of 0.5% whey protein aggregates. In addition to an increase in cheese moisture, cheese yield is also increased. This approach of denatured whey protein inclusion has been used cheese as well for low fat Mozzarella without any apparent effect on physical and sensory properties of cheese (Punidadas et al., 1999).
Inclusion of sweet buttermilk in low fat cheese also helps retain moisture. This is accomplished by the direct addition of sweet buttermilk to milk (Mayes et al., 1994). This process requires the addition of relatively large amounts of buttermilk, up to 30% (Madsen et al., 1966). An alternative approach is to use sweet buttermilk that has been concentrated by ultra-filtration. This approach has been applied to low fat Cheddar cheese (Mistry et al., 1996), low fat Mozzarella (Poduval and Mistry, 1999) and low fat process cheese (Raval and Mistry, 1999). The amounts used were up to 5% ultrafiltered buttermilk, which helped retain moisture and also improved the body and texture of cheeses perhaps because of the inclusion of the milk fat globule membrane in the buttermilk. Concentrated buttermilk also lowered free oil in melted cheese.
Processes involving homogenization have also been developed with the specific goal of improving the body and texture of low fat cheeses. Tunick et al. (1993) reported on the use of milk homogenized at 10,300 and 17,200 kPa for manufacturing low fat Mozzarella cheese. Improvements in textural and melting characteristics of cheeses were reported by such treatment. Homogenization of milk not only reduces the size of milk fat globules the interfacial forces at the new fat globule surface may disrupt casein micelles (Darling and Butcher, 1978) and lead to curd shattering and yield loss. Metzger and Mistry (1995) developed a procedure in which 40% fat cream is homogenized and blended with skim milk to the desired fat content for the manufacture of low fat Cheddar cheese. Homogenization in this manner has minimal effect on milk proteins but provides the needed reduction in fat globule size and consequently an increase in fat globule surface area and numbers. Cheeses had excellent body and texture, less free oil in melted cheese than in control cheeses and improved yield due to increased fat and protein recovery.
Adjunct cultures: Adjunct cultures not only have a role in flavor development in ripened cheeses but may also be used to enhance functionality of low fat cheeses. For example, the proteolytic activity of Loctobacillus casei subsp. Casei is also useful in development of functional properties of low-fat mozzarella cheese (Merrill et al., 1996).
Tungjaroenchai et al. (2001) evaluated the effects of four adjunct cultures with differing levels of amino-peptidase activity on the flavour and texture of a reduced-fat Edam cheese (20% fat) Amino-peptidase activity of Loctobacillus lactis spp. diacety lactis was higher than that of Lactobacillus helveticus (LH 212), Lactobacillus reuteri and Brevibacterium linens (BL 2), respectively but cheeses containing L. helveticus developed the highest levels of free amino acids. Beneficial texture effects were obtained using Loctobacillus helveticus (LH 212) and L. reuteri.
The flavor and texture of a low-fat (9%) ewes milk kefalograviera type cheese were improved significantly by selection of a commercial culture that produced acetate, diacetyl and acetoin from citrate fermentation (Katsiari et al., 2002b). Acetate is the dominant free fatty acid in full-fat Kefalograviera cheese and comprises 34% of all free fatty acids in the mature cheese. The selected commercial culture improved the body and texture and greatly enhanced the flavour intensity of low-fat high-moisture kefalograviera-type cheese compared with the commercial regular starter used in full-fat cheese production.
Katsiari et al. (2002c) found that low-fat Feta-type cheese with flavour similar to that to the full-fat cheese can be made by adding the commercially available adjunct culture cr-213 to the cheese milk. However, the overall quality of this cheese is significantly lower than of the full fat cheese. Low-fat Feta-cheese contain more lactic and citric acids but less butyric acid than the full fat control.
The addition of the adjunct culture had appositive affection butyric acid, propionic acid and acetone content. It is concluded that the use of the adjunct culture could enhance the production of organic acid in low-fat Feta-type cheeses, eventually giving a positive effect on their sensory properties (Manolaki et al., 2006).
Low-fat cheese can be manufactured using the freeze-shocked L. helveticus or L. casei. These attenuated culture have not affected the general composition of the chesses but accelerated the ripening of the cheese samples more distinct effect with L. helveticus. When sensory properties are considered, L. casei has provided more favorable results for the manufacture of low-fat Kasar cheese (Gursoy, 2009).
Use an exo-polysaccharide-producing culture to help improve structure and texture of cheese "Textural attributes are believed to be important criteria in determining the identify and quality of cheese and its consumer acceptability". The texture and fracture properties of a cheese are largely determined by the nature and arrangement of its structural network (Dabour et al., 2006). Exo-polysaccharide acted comparable to a gum. It helped glue the cheese particles together.
The increased exo-polysaccharide improved the pliability of the cheese. Improved the flavor conducts by Agrawal and Hassan (2007) involved the process of ultra-filtration of milk to remove the bitter taste of reduced-fat cheddar cheese made with an expoly sacccharide producing culture. The ultra-filatration process helped diminish the bitter and unpleasant taste from reduced-fat cheese by squeezing all of the extra tasteless liquid from the cheese contents.
Use of encapsulated or ropy exo-polysaccharide (Eps) producing cultures showed improved sherd fusion, meltability and reduction in surface scorching of low-fat Mozzarella cheese (Zisu and Shah, 2007). Upon baking, cheese made with EPS producing cultures exhibited reduced surface scorching and increased sherd fusion after 45 day of storage and maturation to 90 days not required. Given that capsular and ropy forms of EPS have similar beneficial effects an low-fat Mozzarella cheeses when milk is pre-acidified, the selective use of the capsular EPS producing strains over the ropy type is rational when considering the implications associated with slime formation.
The use of an exo-polysaccharide-producing strain of S. thermophilus in Mexican panela cheese increased moisture retention and when higher total solids milk was used, it also increased the fat retention within the cheese matrix. This was reflected in a greater yield of the cheeses obtained and a lower tendency to syneresis. Scanning electron microscopy showed that the EPS bound to the protein matrix of the cheese, the micro organisms and milk fat globules, leading more opened structure of the cheese and producing a network which helped increase the water and fat retention. The higher water and fat content of the ropy cheeses changed its sensory characteristics, giving a softer texture and a creamier product than the control cheeses which was acceptable to the panelists (Jimenez-Guzman et al., 2009).
Fat replacers and other additives: Fat replacers are generally categorized into two groups: fat substitutes and fat mimetic. Fat substitutes are ingredients that have a chemical structure somewhat close to fats and have similar physiochemical properties (Lipp and Anklam, 1998; Kosmark, 1996; Peters et al., 1997). They are usually either indigestible or contribute lower calories on a per gram basis. Fat mimetic are ingredients that have distinctly different chemical structure from fat. They are usually carbohydrate and/or protein-based. They have diverse functional properties that mimic some of the characteristic physiochemical attributes and desirable eating qualities of fat: viscosity, mouth feel and appearance (Johnson, 2002; Duflot, 1996). The classification of fat replacers by nutrient source, energy density, specific application and functional properties reported by Ognean et al. (2006) shown in Table 1.
| Table 1: | Classification of fat replacers by nutrient source, energy density, specific application and functional properties |
The fifth method focused on the criticism that reduced-fat cheese is too dry and lacks a creamy texture. Banks (2004) stated that fat mimetic or water-dispersible fat replacers can help solve this problem". Fat mimetic consist mainly of micro particulates whey protein or carbohydrate-based material. They mimic the properties of fat by entrapping water and giving a sense of lubricity and creaminess". Fat replacers improved the dry, low moisture cheese by creating a smooth, more pliable consistency that was more palatable to consumers.
Reduced fat processed cheese with Lecithin was more similar to full fat control processed cheeses. The use of 0.05% granular soy lecithin or hydrogenated soy lecithin improved texture properties of reduced fat cheese without negatively affecting acceptance scores. Reduced fat processed cheeses containing lecithin were less firm more slippery and smoother than reduced fat control cheeses. Lecithin associated flavors and aromas were present in cheeses containing lecithin as determined by a trained sensory panel but consumer flavor and acceptance scores were not affected. Granular soy lecithin gave more texture improvements to reduced fat processed cheese than hydrogenated soy lecithin. The use soy lecithin improved texture properties without negatively affecting acceptance (Drake et al., 1999).
Abd El-Hamid et al. (2001) replacing milk fat in mozzarella cheese making with Novagel. Dairy-Lo or maltodextrin. Addition of fat replacers enhanced the meltability, lowered oil separation and cheese firmness and improved the microstructure of low-fat Mozzarella cheese. Fat replacers altered the cheese protein matrix and increased the openness of the cheese structure.
The textural properties of 3-mouth old low-fat cheddar cheese manufactured with a B-glucan hydrocolloidal composite denoted as Nutrim, anutraceutical fat replacer were studied by Konuklar et al. (2004). Texture attributes of the cheeses from the sensory panel evaluated by hand feel were all similar. Texture attributes of the cheeses from the sensory panel evaluated by mouth feel were similar for creamy, chewy and grainy, however, the Nutrim cheeses were significantly morepasty. There were not any significant differences for cohesiveness and springiness among the cheeses. In flavour attributes, significant differences were record for buttery, bitter and slarchy characteristics.
Use of commercial oat B-glucan concentrate in low-fat white-brined cheese product affected cheese appearance and flavor in comparison with the control samples. For the cheeses made with the B-glucan concentrate, the yield and extent of proteolysis increased compared to their low-fat counterpart. Moreover, the fortified products exhibited higher levels of short chain fatty acids (lactic, acetic and butyric). The rheological and sensory measurements showed an improvement in the texture of the low fat cheese containing the B-glucan preparation. However, the color, flavor and overall impression scores were significantly inferior to those of atypical white-brined cheese product (Volikakis et al., 2004).
The influence of exo-polysaccharide (EPS), pre acidification and use of two fat replacers, FR1 and FR2 on the textural and functional characteristics of Mozzarella cheese were studied (Zisu and Shah, 2005). Moisture in low-fat Mozzarella cheese was increased with the use F FR1 and FR2 fat replacers leading to improved yield and textural characteristics. Pre-acidification of the cheese milk and use of FR1 further increased the moisture content and yield. Pre-acidified cheese also had on increased level of proteolysis and subsequent hydration of the protein matrix improved their functional behavior. The nature of the fat replacer, however, it had the greatest influence on the microstructure of cheese and its impact on the textural the functional characteristics, FR1 containing cheese showed better melt, stretch and pizza bake performance as compared to FR2 containing cheeses. By combining EPS cultures with the appropriate fat replacer and pre-acidification it is possible to increase the yield of low-fat Mozzarella cheese and reduce maturation time, there by reducing storage periods.
Hennelly et al. (2006) studied the possibility of using inulin gels or solution to replace fat in imitation cheese. Inulin was successfully incorporated into the imitation cheese matrix at a level of 3.44 g/100 g cheese gel or aqueous solution. At this level, it directly replaced 63% of the total fat in the formulation without any significant effect on the melting characteristics. It is recommended, primarily for reasons of convenience and process (temperature) control to add inulin as a hot (80°C) solution rather than a cooled gel.
El-Shibiny et al. (2007) made low-fat processed cheese spreads of good sensory properties comparable to the full-fat cheese spreads with use of Jursalium artickake, whey protein concentrates and simples (R) as a fat replacer. The use of different emulsifying salts had no marked effect on the chemical composition, microbilogical quality, rheological properties and sensory properties of the produced processed cheese spreads.
Lobato-Calleros et al. (2007) used emulsified canola oil and whey protein as fat replacer. Scanning electron micrographs showed that the total or partial substitution of the milk fat by emulsified canola oil and or whey protein concentrate produced cheese with different structures from that of the full-milk fat cheese. When whey protein concentrates predominated denser, compact and continuous protein matrix was produced. In contrast, when emulsified canola oil predominated, looser, more disrupled protein matrix was formed. These different cheese microstructure exhibited differing textual characteristics, Increasing Concentration of the emulsifiers blend (indirectly canola oil), whey protein concentrate and/or milk fat increased the values of the textural characteristics of the cheeses.
Use of Arabic Gum improves the textural and rheological properties of Iranian low-fat white cheese. The cheese treated with 0.5 g of Arabic gum was close to full fat control cheese. However, by increasing Arabic gum’s concentration to 0.75 g, these indices showed high promotion and were close to reduced fat control cheese. Arabic gum in low level concentration can be used as a fat replacer to decline energy producing feature and its texture improvement as well (Shendi et al., 2010).
Novel fat removed method: Whetstine et al. (2006) stated that the flavor release is different in the mouth with reduced-fat products than in full-fat products because hydrophobic flavor compounds have a higher sensory threshold in oil than they do in water. When fat molecules are extracted from milk before cheese is made, there are less fat molecules for the sensory compounds to bind to, resulting in a lack of flavor reduced-fat cheese.
Nelson and Barbano (2004) preceded Whetstine et al. (2006) and designed a method that physically removed the fat content from full-fat aged cheddar cheese after it had been processed. Full-fat cheddar cheese contains the full maturity of flavor and by extracting the fat after the cheese has aged, the researchers theorized that the non-fat cheese would retain the original flavor, thus making low-fat cheese comparable in taste to full-fat cheese. The process was constructed as follows: for the extraction method, the researchers selected three samples of palatable Full-fat cheddar cheese. The cheese was grated, weighed and placed in separate bottles with a combination of volatile compounds. Each bottle was mixed for 30 min by Roto mix and centrifuged for ten minutes, which allowed the fat to separate from the cheese. The cheese, after purification like process, was served to panel of 12 to evaluate the flavor. There were only slight differences in taste between the full-fat and reduced-fat cheese. The process allowed the researchers to remove 50% of the fat from the full-fat cheddar cheese, while maintaining the same nutty flavor of the original block of cheese. The reduced fat cheese made from the fat removal process was also softer and had a comparable melting profile to full-fat cheese (Fig. 2 and 3).
| Fig. 2: | Typical melting outline of fat from full-fat Cheddar cheese |
| Fig. 3: | Typical melting outline of fat from reduced-fat Cheddar cheese produced by the fat removal process |
Supercritical Fluid Extraction (SFE) technology can be used in the dairy industry to develop low-fat cheese with flavor to match that of full-fat cheese (Yee et al., 2007). The SFE from mature cheddar and parmesan cheeses allowed for the reduction in total fat, with no need for modification in formulation. A maximum fat reduction of 51% for cheddar cheeses and 55.56% fat reduction for parmesan cheese. The objective of this investigation was to develop lower fat cheddar and parmesan grated cheese using SFE and characterize its flavor profile comparative to a full-fat product. Specifically, enabling flavor compounds partition between the matrices of cheese and extracted lipids.
CONCLUSION
| • | In the near future all of the concern for low-fat cheese will be solved with new technology. Dairy research would allow consumers to enjoy their cheese without feeling guilty, from the high fat content. The research would also benefit producers who value high-quality products |
| • | Each method was built off another idea for creating healthful and flavorful cheese. Producers must take risks to create products that meet the consumers need. Consumer could soon be on the way to eating nutritious and delicious food with the onset of dairy research |