Cheese

Cheese has always been a safe bet for Food . This is the result of aprocessing milk since ancient writings testify to manufacture some threethousand years BC in lower Mesopotamia . Valuable source of protein , the cheese wasa first means of preserving milk , a highly perishable commodity .However , the resulting milk coagulation and draining the curd only provide stabilityrelative and varies cheeses that are dairy products "live" . Thus , if theproteolysis is a fundamental phenomenon during ripening , this enzymatic activitycontinues even at low temperature and taken beyond a certain stage to impairedcheese .Several methods have been developed to prolong the life of the cheese . theProcessed cheese is a much more recent preparation, which has a good stabilizationfurther milk proteins , any retaining more or less finished product appearancea cheese .In 1911, Swiss WORKERS , GERBER STETTLER Walter and Fritz , proceeded to castEmmental cheese of using sodium citrate as an iron salt leading toobtaining a product known as " Schachtelkäse " ( Meyer, 1973) .Subsequently , it was shown that other cheeses such as Cheddar aresubject to the recast by adding other types of melting salts such as sodium phosphates( GUINEA et al. , 2004).Algeria is the largest consumer of milk and dairy products in the Maghreb and upand the third largest in the import of milk and milk products after Italyand Mexico ( AMELLAL , 1995). Despite the immense diversity of types of cheese inthe market, cheese portions emerge with better consumer preferenceAlgeria at the expense of other types of cheese that are considered luxury goods .introduction2The rising price of cheese is the result of higher material costsraw materials of milk origin, such as cheese, casein and caseinates , whey andfat dairy origin . In the literature, research like those ofMOUNSEY et al. (2008a), NORONHA et al. (2008a) and KIZILOZ et al. (2009 ) have beenthe full or partial commutation of the fat and protein source materialby dairy raw materials of plant origin, whose aim is to reduce costsproduction. This switching produces modifications of the structure and characteristics ofrheology , but the flavor of the finished product, which will determine its acceptability withconsumer .In this context, the work presented in this thesis aims at a better understanding ofphysicochemical phenomena occurring during the manufacturing process of the specialtycheese , a determination of the impact of partial substitution of milk proteins bycrosslinked starch ( hydroxypropyl distarch phosphate E 1422 ) on viscosity andflow as well as the texture of the final product properties and finally a determination ofexisting correlations between physicochemical parameters and sensory characteristics.Apart from the introduction and conclusion, the manuscript , the result of this work isorganized into three main parts.The first part is a literature review on cheese specialtiesmelted. First, the raw materials of specialty cheese are presented.After a review of preliminary technology , bibliographic datatechnology of melting were collected. The quality control procedures are thendescribed .In the second part is then exposed the range of materials and methods setimplemented as part of the experimental work . Characterization techniques propertiesphysicochemical and rheological are detailed. A small snippet of this part was devotedfor bacteriological analysis and experimental protocols are specified. three testssensory evaluation of the products are discussed in this study namely the triangular test, theplacement test by rank and hedonic test. Particular attention was paid to thedescription of the principles and choices that govern each method so that the operatingdata is facilitated.introduction3The results are then developed in the third part where they are discussed in threesteps . First is presented the evolution of physicochemical parameters and thethe viscosity and flow properties during the manufacturing process . Thereafter, the state andMorphology of cross-linked starch granules in the final product are described . The second stagefocuses on the results obtained during microbiological testing. Finally, the results ofsensory analyzes are developed and a discussion based on the overall resultsphysicochemical and sensory allows to summarize interactions between parametersphysicochemical and sensory characteristics .Chapter I : Literature Synthesis4Chapter I : Literature Synthesis1. SPECIALTY CHEESECheese specialty is obtained by mixture of cheeses of different origins andrefining stages with melting salts ; This mixture is ground and then heated under vacuumpartial and constant stirring until a homogeneous mass ( PACKAGE , 1988;GUINEA et al. , 2004). Other dairy and non -dairy ingredients may beadded to the mixture .1.1 . definitionThe name " specialty cheese fondue " is reserved for dairy products , whichminimum solids content is 25 grams per 100 grams of product preparedfrom cheese and other dairy products. This product is obtained by techniquestreatment which include melting and lead to emulsification of the raw materials and musthave undergone , during its production , a temperature of at least 70 ° C for 30 seconds orany other combination of time and temperature of equivalent effect ( Official Journal , 2007).1.2 . Historical and economic overviewThe ability to produce the cheese was treated for the first time in 1895. Themelting salts were not used and the product failed . The first cheese successfulwherein the emulsifying salts were used , was introduced in Europe in 1911 and the U.S. in1916 Kraft ( MEYER, 1973).According to FOX and McSWEENEY (1998) , melting cheese has several advantages ;are:• A certain amount of cheese that is difficult or impossible to marketcan be used ;literature review5• Mixing different varieties of cheese and other raw materials notdairy can give different melted cheeses view consistencyflavor and shape;• they have a storage stability at moderate temperatures , which reduces thecost of storage and transport ( Christensen et al, 2003 . )• They are more stable than natural cheeses during storage;• an excellent nutritional value , especially as a source of calcium andprotein for children, and ability to meeting the nutritional needsthey are enriched with vitamins and minerals ( and ZHANG MAHONEY , 1991;SUKHININA et al , 1997) . ;• They are attractive to children who score pushed the flavors of cheesesnatural .The production of the cheese product in different countries is illustrated inTable I- 1. The overall production is estimated at an amount of 2 million tons / year, which isequivalent to 13 % of total cheese .Table I- 1. World production of cheese specialty between 1995 and 2000 (in thousands oftonnes) ( GUINEA et al. , 2004)Country 1996 2000 Change 1996/2000( % )France 126 134 +1.5Germany 157 171 +2.2Italy 20 20 +0.1Belgium 54 55 +0.8Spain 39 37 -1.3USA 1081Australia 50Japan 97Algeria is an importer of cheese country. The evolution of importscheeses showed a rate of 75 % between 1995 and 1998 (Table I-2) . This shows thatcheese production in Algeria was weak and could not meet market needsAlgerian .literature review6Table I -2. Evolution of imports of cheese in Algeria between 1995 and 1998 (in tonnes)( PADILLA and GHERSI , 2001)1995 1996 1997 1998 Change 98/95Volume in%9051 12 260 16 733 15 862 6 811 751.3 . classificationDepending on the fat in dry matter (MG / ES) , processed cheese candivided into seven categories (Table I-3) .Table I-3 . Classification of cheeses (DFI , 2009)Category according tofat contentminimum contentMG / ES g / kgcheeseES minimum in g / kgcheesespreadsES minimum in g / kgDouble cream 650,530,450550 cream 500 450Fatty 450,500,400Three - quarter fat 350,450,400Semibold 250400300Quarter - fat 150,400,300Lean than 150,400,300For the cream cheese and cheese spread whose name includesname of a variety of cheese , only the following products can be used , besides thecheese (DFI , 2009):• milk fat ;• edible salt ;• drinking water ;The composition must meet the following requirements :• If the specific name includes a designation of origin , only the cheesequestion may be used for casting ;literature review7• If the name includes a specific indication from the mixture usedfor casting must contain at least 750 g per kilogram of the variety mentioned. The remainder ofcheese must be comparable ;• any other denomination cheese , the mixture used to melt must containper kilogram over 500 g of cheese in question .1.4 . nutritional valueThe specialty cheese has all the nutritional characteristics of the productsDairy composing . It provides the body with the most essential nutrients for abalanced diet (Table I-4) . Requiring no preparation, this is an excellentway to provide energy to our body builders and elements necessary for itsoperation (lipids , carbohydrates, proteins , minerals, vitamins , etc.). ( MEYER, 1973).Table I-4. Composition of cheese ( MEYER, 1973)componentsComposition per 100g of cheese45% fat in 60% MG ES ESWater 51.3% 50.6%Fat 23.6% 30.4%Protein 14.4% 13.2%1.26 mg 1.01 mg sodium65.0 mg Potassium 108 mgCalcium 547.0 mg 355.0 mgPhosphorus 944.0 mg 795.0 mgVitamin A 0.30 mg /Vitamin D 3.13 mg /Vitamin B1 34.0 mcg 40.0 mcgVitamin B2 0.38 mg 0.35 mg70.0 80.0 mcg Vitamin B6 mcgBiotin 3.60 mcg 2.80 mcgFolic Acid 3.46 mcg 3.40 mcg0.25 mcg Vitamin B12 0.25 mcgVitamin C Traces Tracesenergy value( KJ / kcal )1178/282 1490/339literature review82 . RAW MATERIALS TECHNOLOGY SPECIALTYCHEESESpecialty cheeses are made from raw milk and notinstead of dairy milk ; casein and caseinates , whey, fat and dairy originvegetable , starch, emulsifying salts , additives ... ( caric , 2000 FOX et al , 2000 . HUANG et al .2010) .2.1 . Raw milk2.1.1 . Natural cheeseMelted cheese and specialty cheese are dairy products in which theCheese is a dairy ingredient mainly used as raw material ( CommissionCodex Alimentarius , 2004). A selection of suitable natural cheese is paramount tomaking a specialty cheese quality ( ROOM DAURELLES , 1997).According BOUTONNIER (2002) , the cheeses are characterized by :o the pH ;o the total dry (EST ) extract;o fat (MG) ​​;o solids- (ESD) ;o the nature of the texture in association with the structure of the dough ;o the level of mineralization ( % by mass of calcium on fat dry extract) ;o casein content relative.These criteria are fundamental to select different cheeses depending on thetechnological process and materials used on the one hand and the type of end product desiredother ( USDA , 2007).The choice of cheeses used is between Cheddar, Emmental, Gruyère ,Mozzarella and other cheeses pressed ( McSWEENEY et al. , 2004) based on thetype, flavor , maturity, consistency, texture and acidity ( ROOM DAURELLES ,1997) .2.1.2 . Other dairy raw materialsMoreover cheese , other dairy raw materials are used for theprocessed cheese . Mention may be made , milk protein concentrates , milk powdersskimmed milk, whey, lactose, casein , caseinates , whey protein , coprecipitated , cream, butterand anhydrous milkfat (FOX et al. , 2000).literature review92.1.3 . premeltThis is already melted cheese resulting from the recovery of the dough contained indifferent locations of the product circuit in the workshop after production and in particular tolevel conditioning . It was found in practice that when she was recast , the premeltbehaves in terms of the colloid chemistry as a cheese has been exposedfor some time now to chemical phenomena , physical and mechanical processcast. Thus, premelt strongly transmits the physicochemical modification processthe structure in which it freshly melted cheese is added . Therefore, creaming ismuch faster than in the absence of premelt ( Berger et al. , 1993).But for this addition to be profitable, the premelting should be good textural ,that is to say " creamy " and not surcrémée , otherwise cause surcrémage any doughmelted cheese. Its melting process regulator role above all is justified in the case ofSpreads of manufacturing products and the rate of incorporation varies from 2 to 10% by weight accordingthe nature of the raw materials used and the type of texture searched for productsfinished . It is particularly interesting in the case of UHT processing for which the doughafter sterilization is extremely fluid and the relatively delicate creaming ( Patart , 1987).2.2 . Non-dairy raw materials2.2.1 . waterThe moisture content of cheese is generally low and since the powder is incorporated , itis absolutely necessary to bring water to the mixture. This allows to solubilize anddispersing the protein and thus emulsify the fat free . This water must befood grade , that is to say with a low content of microorganisms andchemical contaminants such as nitrates. It may be provided in liquid form or in aseveral times at different times of the production but still cold to ensureconstant amount of water of condensation upon heating . In the case of treatmentthermal type UHT sterilization , this water is injected in vapor form in a range120 to 140 ° C and a pressure of from 2.105 to 4.105 Pa ( Marshall, 1990; BERGER et al .1993; GLIGUEM et al. , 2009a).Softening and increasing the ability to redesign cheese specialtiescan be attributed to the effect of the increased content of free water, increasing thevolume of fat globules ( GLIGUEM et al. , 2009b) and lower protéinesprotéines interactions.At a humidity of 50 g/100 g , the water is almost entirely related caséique network ,it will be served as a water of hydration to 52 g/100 g moisture capacityliterature review10caséique network hydration is exceeded resulting in a more water called "free water " .Any increase in humidity leads to an increase of the free water and the optimum is54 g/100 g ( Hennelly et al . 2005).2.2.2 . Vegetable raw materialsThe vegetable raw materials are used for the manufacture of cheesemelted imitation ( MOUNSEY et al , 1999; . 2008; KIZILOZ et al, 2009 . ) . Usingraw materials of plant origin prohibits the term " cheese " and forced toname " specialty cheese fondue " ( BOUTONNIER , 2002).2.2.2.1 . vegetable fatsCheaper than milk fat , they also have the advantagean absence of cholesterol and high levels of poverty in saturated fatty acids ( BACHMANN,2000) .2.2.2.2 . vegetable proteinsStudies have been undertaken on replacing casein in specialtiescheese by various types of vegetable proteins ; soy protein , peanut andwheat gluten . These have a high capacity of water absorption and generate athick and low consistency fluid . They must be incorporated at low doses ( 2-3 % )( Chen et al , 1979 . LEE et al , 1981 . TARANTO and Yang , 1981; YANG and TARANTO ,1982; Yang et al , 1983. ; KIM et al , 1992. ; ORTEGA - FLEITAS et al. , 2001).2.2.2.3 . starchNo other food ingredient competes with starch in terms of versatility andapplication in the food industry . The starches were used for diversificationtextures ; improving the appearance of the products ; simplification of the statementlabel ; reducing production costs; ensuring the consistency of the products andprolonging shelf life ( Taggart et al . 2009).• SourceDespite the ubiquity of starch in the nature, the number of commercial sources is veryreduced. The sources of the most important are maize starch , potato , wheat,tapioca and rice. Several grains such as wheat , corn and waxy maize are grown inAmerica and Europe , while the potato from cold northern regionsliterature review11European . Tapioca is from Brazil , Thailand and Indonesia , and rice in Asia. themorphology and size of the starch granules are shown in Table I-5 .Table I- 5. Characteristics of starches and starch according to their botanical origin( Nayouf , 2003)Corn Corn propertieswaxyapplelandcassava Wheat- Size of the starch grains ( microns ) 2-30 2-30 4-35 2-55 5-100- 28 % amylose < 21 February 17 28- Power of swelling at 95 ° C( g / g )24 64 1150 71 21• Food crosslinked starchCrosslinking is to create inter-or intramolecular bridges in the granulestarch ( Figure I- 1 ) . Found on the market for phosphates and adipates Distarch onbase waxy maize and tapioca starches for cooking , and based on waxy maize starch andpotato for precooked or gelatinized starches ( STOCK , 2008).This is accomplished by adding wetting agents to the suspension of starchmaintained at a temperature below the gelatinization temperature (below 50 ) . ratecrosslinking agent , that is to say the number of inter-or intramolecular bridges in the granulestarch is adjusted according to the resistance that must be imparted to starch : this number variesabout 1 bypass to 3000 glucose units for a weakly crosslinked starch 1 bypassto 300 glucose units for highly crosslinked starch ( TAKACHE , 2006).Figure I-1 . Crosslinking of starch ( OAK , 2004)literature review12The crosslinking process occurs during the formation of bonds between twostarch molecules and leads to an increase in the degree of polymerization of the molecules( Figure I-2 ) . The structure of the granule is increased to make it more resistant to swelling andbreak , the latter being caused by a high temperature and shear .These starches are obtained under conditions of low temperature ( 40-50 ° C ) andvarying pH , as the polyfunctional reagent ( the acid and aldehyde derivativesBasic for others) . The degrees of crosslinking achieved is generally very low ( 0.5 % )however are sufficient to radically alter the properties of starches ( BULEONet al . 1990). Such modified starches are employed in the manufacture of productspackaged as sterilized boxes, hot extruded products to give themgreater expansion and finally , in products heated at high temperatures (over100 ° C) (Würzburg , 1995).Figure I-2 . Crosslinking of the starch in the presence of phosphorus oxytrichloride , in an alkaline mediumand for a temperature of between 30/50 ° C ( BULEON et al . 1990)• Hydrothermal Behavior of crosslinked starchesIn a hydrothermal treatment , the swelling of the crosslinked starch granulesoccurs at a temperature close to the temperature of gelatinization of native starchreference . Structural changes accompanying gelatinization , are found oncrosslinked starches , but the solubilization of granular content is little or no ( TAKACHE ,2006). Chemical bridges provide sufficient integrity to maintain grainstarch in the form of swollen granule . Unlike native starches , crosslinked starcheskeep this inflated state of granules which may disappear when the firing temperature increases,mechanical shear forces increase and when the pH of the medium decreases tobreaking of chemical bridges ( TAKACHE , 2006 STOCK , 2008).2.2.3 . Texturing AgentsThese are hydrocolloids that in the presence of water or a strong thickening powergelling agent and a stabilizing action vis- a-vis the product water . They may be of animal originliterature review13( gelatin ), vegetable ( starch , guar gum, locust bean gum, alginates , carrageenans ,carboxymethylcellulose ... ) or produced by fermentation ( xanthan gum and gellan )( KIZILOZ et al. , 2009). Their role is to improve the consistency and smoothness of the specialtycheese , and avoids any syneresis and thus facilitate the separation ofpackaging in contact with the product. In France , the use of these additions prohibits the designationcheese and forced the name "specialty cheese fondue ." quantitiescommonly employed vary from 0.1 to 0.25% by mass . However, these agents do texturecan not completely replace the melting salts . Their use is justified in morethe case of the manufacture of cheese from fresh cheeses that are of Contentsfirst highly demineralized and low in protein . In this particular case , the associationbetween agents texture and melting salts gives excellent results both in terms ofphysicochemical and stabilization in terms of mouthfeel ( GUINEA et al, 2002 . ;LUCEY et al . 2003).2.2.4 . Melting saltsThe emulsifying salts used in process cheese manufacture are substantially saltssodium citric acid and phosphoric acid ( Gupta et al . , 1984) ( Table I- 6 ) .Table I -6. Incorporation rate of acid and melting salts ( BOUTONNIER 2002)codeEuropeanType of acid or saltmeltingrateincorporationregulationE 330 Citric AcidSufficient (1)E331 Sodium citratesE 338 Phosphoric acid 20 mg.kg - 1 in totalE 339 sodium orthophosphates 20 mg.kg - 1 in totalE 340 Potassium phosphates 20 mg.kg - 1 in totalE 341 calcium orthophosphates 20 mg.kg - 1 in totalE 450 Diphosphates sodiumpotassium and calcium 20 mg.kg - 1 in totalE 451 sodium Triphosphatespotassium and 20 mg.kg - 1 in totalE 452 Sodium polyphosphates ,potassium and calcium 20 mg.kg - 1 in total(1) No toxicity has been demonstrated ; ADI (Acceptable Daily Intake ) has been fixed.literature review14The main properties for which the melting salts are used are:• The power complexing or chelatingIt can be defined as the ability to bind metal cations to formsoluble complexes ; this property sequestration What polyphosphates can removecalcium from the protein system ( WAGNER WAGNER- and Hering , 1981; LAMURE , 1988;SCHÄR et al . 2002). This results in a rearrangement of the protein molecules and exposurehydrophilic groups . The evolution of the calcium during this process is a pointsignificant ; as well as the state of phosphates and , secondarily , those of potassium andmagnesium ( HORNE , 1998) .• The buffer capacityThe adjustment of the pH of a formula of cheese is an important step inthe manufacturing process . The pH during the process tolerated is between 5.6 and 6.1 ,the buffering salts affects the melting protein conformation , hydration andcalcium sequestration ( GUINEA et al. , 2004). Its effect on the texture was clearlydemonstrated by Karahadian et al. (1984 ) . The different salts of iron can, for theirpower buffer to adjust the pH of the product to the correct value ( Gupta et al , 1984. ;ROOM al. , 1997). However , SWIATEK (1964 ) reported that the increasedconcentration of polyphosphate has a lesser effect on the pH .• bacteriostatic effectSome salts have a bacteriostatic effect , this is especially true of polyphosphates andorthophosphates that can markedly inhibit the growth of several species ofSalmonella bacteria including Gram- positive Staphylococcus aureus , Bacillus subtilis ,