World Applied Sciences Journal 23 (7): 914-925, 2013ISSN 1818-4952© IDOSI Publications, 2013DOI: 10.5829/idosi.wasj.2013.23.07.13122

Corresponding Author: Samah M. Shalaby, Food Science Department, Faculty of Agriculture, Ain Shams University,Shoubra EL-Khaima, Cairo, Egypt.

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Quality of Novel Healthy Processed Cheese AnalogueEnhanced with Marine Microalgae Chlorella vulgaris Biomass

A.G. Mohamed, B.E. Abo-El-Khair and Samah M. Shalaby1 2 3

Dairy Science Department, National Research Science, Dokki, Giza, Egypt1

Fertilization Technology Department, Algal Biotechnology Unit,2

National Research Centre, Dokki, Giza, EgyptFood Science Department, Faculty of Agriculture, Ain Shams University,3

Shoubra EL-Khaima, Cairo, Egypt

Submitted: May 26, 2013; Accepted: Jul 6, 2013; Published: Jul 19, 2013Abstract: Cheese analogue (Ch A) is processed cheese-like product, a nutritious food, can be healthy andattractive when redesigned to be prepared with the addition of a natural ingredient, being Chlorella vulgaris.This microalga is recognized as a rich source of protein, fatty acids, fiber and ash. C. vulgaris also representsa valuable source of essential vitamins and minerals. Chlorella has health benefits, as assisting disorders suchas gastric ulcers, wounds, constipation, anemia, hypertension, have immune-modulating and anticancerproperties and is a promising ingredient in the food industries. Cheese analogue (Ch A) treatments wereenriched with C. vulgaris (1, 2 and 3%) and evaluated for chemical, physical and sensory properties, withinthree months of cold storage. Chlorella biomass cheeses were richer in the protein, carbohydrates and fibercontents than control samples. On the other hand, addition of Chlorella biomass to the cheese gave productsmore firmness and gives a stronger network and leads to lower oil separation and meltability values thancontrol. The sensory evaluation indicated that addition of 2% C.vulgaris in Ch A did not have any effect onthe overall acceptability of Ch A and in the same time introduced a new healthy alternative Ch A for a healthierlifestyle.

Key words: Microalgae Chlorella vulgaris biomass Processed cheese analogue

INTRODUCTION started in the early 1960s (Japan) and nowadays

Modern food industry leads to cheaper, healthier and commonly sold in the form of tablets, capsules or liquids.more convenient products, in response to increasingly Additionally, there is an increasingly growing market forconsumers demand. Microalgae are an enormous food products with microalgae addition such as pastas,biological resource, representing one of the most biscuits, bread, snack foods, candy bars or gums,promising sources for new products and applications [1]. yoghurts, drink mixes, soft drinks, etc., either as nutritiousThese microscopic organisms can be grown under certain supplement, or as a source of natural food colorant [3].controlled environmental conditions that can stimulate or In Egypt, algae production was achieved as early asinhibit the biosynthesis and accumulation of bioactive 1970s aiming at the massive production of non-traditionalcompounds in large amounts. The possibility of not only protein rich food. Assisting of all inputs was fullyharvesting microalgae but also growing them at different reported by El-Sayed [4]. In some countries such asconditions enables its use as natural reactors at a large Germany, France, Japan, USA, China or Thailand, foodscale [2]. Some microalgae species, such as Chlorella and production and distribution companies have alreadySpirulina, have been used for many centuries as a started serious activities to market functional foodsnutrient-dense food in Asia, Africa and Mexico. However, with microalgae and cyanobacteria (blue-green algae).commercial large-scale production of microalgae only The biotechnological exploitation of microalgae resources

microalgae are mainly marketed as food supplements,

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for human nutrition purposes is restricted to very few nutritional supplements (e.g. fiber, fatty acids andspecies, due to the strict food safety regulations,commercial factors, market demand and specificpreparation [1]. Therefore, microalgae can be used toenhance the nutritional value of food products, due totheir well balanced chemical composition as well as asource of highly valuable molecules, such as proteins,carotenoid pigments, vitamins, fatty acids, sterols,polysaccharides, among other biologically activecompounds, presenting potential health benefits.However, foods supplemented with microalgaebiomass might be sensorial more convenient andvaried, thus combining health benefits withattractiveness to consumers [5]. The green alga Chlorellavulgaris is a unicellular green micro-alga that isubiquitous in freshwater environments. The nutritionalvalue of C. vulgaris was initially determined in1950s–1960s [6]. It is also known as one of the earliestforms of life, was the first microalga isolated as a pureculture, by Beijernick in 1890s as mentioned by Guiry [7].It has been used as an alternative medicine in the Far Eastsince ancient times and it is known as a traditional food inthe Orient, being considered as a potential source of awide spectrum of nutrients. In addition to, it widelyproduced and marketed as a food supplement in Japan,China, U.S and Europe, though it is believed that it doesnot possess GRAS status and the toxicological testrevealed the absence of any toxic effects in C. vulgaris[8]. The nutritive value of outdoor or indoor culturedC. vulgaris is of interest to the food industry, especiallyin countries where the weather conditions do not allowmassive culture of higher plants. Chlorella has healthbenefits, such as assisting disorders such as gastriculcers, wounds, constipation, anemia, hypertension,diabetes, infant malnutrition and neurosis. It has alsobeen shown to have immune-modulating and anticancerproperties [9-15]. Use of Chlorella vulgaris extractmight be considered as an adjunct therapeutic strategyto combat hepatic disorders and other oxidativestress-related diseases [16]. Feeding micro-algae to elderlypeople or animals has been demonstrated to protect fromage-dependent diseases, particularly cardiac hypertensionor hiperlipidemia [17-20]. However, Chlorella vulgaris hasbeen named green healthy food by FAO, rich in nutrients,such as proteins, total lipid, total carbohydrate, minerals,dietary fibers, antioxidants and vitamins [21]. C. vulgarisbiomass has already been used experimentally in feed[22-25] and food products, such as pasta products, buttercookies and its polyunsaturated fatty acids are added toinfant formulas [26, 27]. The incorporation of this biomasscan provide a coloring effect and other functionalcharacteristics such as antioxidant activity and providing

oligoelements). Cheese analogue (Ch A) is processedcheese-like product in which milk fat, milk protein or bothare partially or wholly replaced by non milk-basedcomponents. They are manufactured by blendingvarious edible fats/oils, proteins, other ingredients andwater into a smooth homogenous blend with the aidof heat, mechanical shear and emulsifying salts [28].The market of analogues has grown recently due to thesimplicity in producing them and the partial substitutionof milk ingredients by cheaper vegetable ones, factorsthat allow for a reduction in product manufacturing costs[29, 30].

This study’s goal is to develop a new healthyprocessed cheese analogue (Ch A) enriched with differentratios of Chlorella vulgaris biomass (1, 2 and 3% w/w) inthe Ch A formula. Then assessing the changes in thechemical composition, physical properties and sensoryacceptance that caused by this addition.

MATERIALS AND METHODS

Materials: Chlorella vulgaris biomass in the form offreeze-dried was obtained from Algal Biotechnology Unit,National Research Centre, Dokki, Giza, Egypt. Cleangrowth was performed within 1200 L Zigzagphotobioreactor [31] in the presence of the growth mediaas early described by El-Sayed et al. [32]. For harvestingand cleaning of the obtained biomass a series ofprecipitation and washing was performed using tap waterand cooling centrifuge (HEIDELBERG RUNNE, RSU-20).Ras cheese (one month old), matured Cheddar cheese(8 months old), sodium chlorides and sugar werepurchased from local market at Cairo, Egypt. Kasomelemulsifying salt K-2394 was obtained from Rhone-PoulencChimie, France. Low heat skim milk powder and butterwere from Irish Dairy Board, Grattan House, Lower MountSt., Dublin, Ireland. Chemical composition of theingredients used in the manufacturing of Ch A ispresented in Table 1.

Preparation of Acid Casein: Acid casein used in thisstudy was prepared as described by Sawhney et al. [33].Fresh raw buffalo’s milk was obtained from the herd of theFaculty of Agriculture, Ain Shams University, Cairo,Egypt. The fat was separated from milk to get the skimmilk of less than 0.5 g/100 g fat content and the skim milkwas pasteurized and cooled to 37°C. Hydrochloric acidsolution (1.0M) was added to the milk as coagulant andthe precipitation was carried out at 37°C and pH 4.7.As soon as the curd was settled, the whey was removedthen the curd was washed with fresh water at 41°C and

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pressed. The chemical composition of acid curd issummarized in Table 1.

Table 1: Chemical composition (%) of the ingredients used in manufacture of processed cheese analogue

Ingredients---------------------------------------------------------------------------------------------------------------------------------------------------------------------

Analysis (%) Cheddar cheese Ras cheese Skim milk powder Butter Acid casein Chlorella biomass

Total solids 65.80 54.81 96.00 84.00 47.02 94.17Fat 34.80 24.77 0.97 81.99 ND 12.18Crude protein 25.47 22.26 37.13 ND 43.01 351.451 1 1 2

Ash 5.42 5.76 7.89 ND 2.82 9.50Carbohydrate 0.10 1.64 47.43 ND ND 11.86Fiber ND ND ND ND ND 9.18

Protein% - N × 6.38. Not determined. protein% - N × 4.381 2 3

Table 2: Composition (kg/100kg) of different blends used in manufacture of Cheese analogue treatments

Ratios of Chlorella vulgaris biomass (%)----------------------------------------------------------------------------------------------------

Ingredient Control 1 2 3

Cheddar cheese 12.80 - - -Ras cheese 38.44 - - -Skim milk powder 5.12 5.75 5.75 5.75Butter 10.26 25.52 25.52 25.52Acid curd - 32.89 32.89 32.89Salt - 1.00 1.00 1.00Sugar - 1.00 1.00 1.00Emulsifying salt 2.50 1.85 1.85 1.85Chlorella biomass - 3.00 4.00 5.00Water 30.88 28.99 27.99 26.99

Total 100 100 100 100

Manufacture of Cheese Analogue (Ch A): Cheese and analyzed when fresh and monthly up to 3 months ofanalogue (Ch A) was manufactured as described by cold storage at 7°C.Savello et al. [34]. All experimental Ch A treatments Analytical Methods:were formulated to yield Ch A with 50-55% moisture and Chemical Analysis of Algae: Chlorella vulgaris48-50% fat-in-dry-matter. Control processed cheese was biomass nutrient profile was determined by AOACmade of young Ras cheese and matured Cheddar cheese standard methods [35] in terms of moisture, ash,as a base blend. Ch A treatments were manufactured by protein, fat and fiber contents, total carbohydratepartial replacing of the base cheeses (Ras and Cheddar) contents were calculated by difference. Fatty acidswith acid casein curd and Chlorella vulgaris biomass in profile was determined using gas chromatographyratios of 1, 2 and 3% as shown in Table 2. (GC Hewlett Packard 6890) according to the

Process cheese and Ch A treatments were prepared methods described by AOAC [35]. For amino acidby blending the dry ingredients with previously warmed profile, the analysis was carried out as described(50°C) milk fat into the processing batch type kettle of 10 by AOAC [35] using Eppendorf Biotronic LC 3000kg capacity, at the pilot plant unit of the National amino acid analyzer (Eppendorf-Biotronic, Hamburg,Research Centre. Cooked was done using direct injection Germany).of steam at pressure of 1.5 bar to 66°C with continuousagitation for 4 min. The pH was adjusted to 5.80 using Chemical Analysis of Ch A: The Ch A samples wascitric acid or sodium hydroxide. The blends were further tested for fat content (using Gerber method) andthen heated to a final temperature of 82°C in approximately protein content (using micro-Kjeldahl method) as4 min. The blends were held at 82°C for 1 min to add the described by Ling [36]. Salt content wasbiomass, prior to filling into tin cans then stored at 7°C determined as described by Bradley et al. [37].

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The moisture and ash contents were determined species biomass is one of the main reasons to consideraccording to the method by AOAC [35]. The pH values them as an unconventional source of protein. In addition,were measured using pH meter model Cole-Armer the amino acid pattern of almost all algae comparesInstrument Co., USA. favorably with that of other food proteins. Table 4 show

Organoleptic Evaluation: Sensory attributes of Ch Asamples were evaluated by the staff members atDepartment of Dairy Science, National Research Center.Samples were evaluated according to the scale mentionedby of Awad et al. [38] as follows:

Firmness: (1 = very soft, 7 = very firm).Stickiness: (1 = very sticky, 5 = not sticky).Crumbliness: (1 = very crumbly, 7 = not crumbly).Sliceability: (1 = poor sliceability, 5 = good sliceability).General acceptability: (1 = very poor acceptability, 7 =very good acceptability).

Statistical Analysis: All data were expressed as meanvalues. Statistical analysis was performed using one wayanalysis of variance (ANOVA) followed by Duncan’sMultiple Range Test with P 0.05 being consideredstatistically significant using SAS program [39].

RESULTS AND DISCUSSION

Chemical Composition of Chlorella vulgaris Biomass:The chemical composition of C. vulgaris used in ourexperiments is shown in Table 3. It can be seen that themain component is the protein which represents morethan 50% of the chemical composition of C. vulgarisbiomass. The other components such as lipid,carbohydrates, fiber or ash were in the range of 9-12%.These results are in the same trend of Yusof et al. [40],who reported that the protein, ash and fiber contents werequite high in Chlorella vulgaris biomass in all cultureconditions, which is comparable with most microalgae,such as Enantiocladia duperrehyi, Amansia multifidaand Hypnea musciformi. Also, the results are inagreement with those obtained by Gouveia et al. [8], whomentioned that C. vulgaris biomass has a high proteincontent (~ 40%), that may have reinforced the doughsystem of the cookies. On the other hand, the obtainedresults are different with that of Fradique et al. [41], whofound that C. vulgaris (green or orange) were so high inthe ash content being more than 34%. The differences incultivation conditions are the main source of differencesin protein and minerals contents of one strain of algae[42].

The high protein content of various microalgae

the presence of nine of essential and seven of

Table 3: Chemical composition of Chlorella vulgaris biomassComponent (%)Moisture 5.83Dry matter 94.17Crude protein 51.45Carbohydrates* 11.86Crude lipid 12.18Crude fiber 9.18Ash 9.50*: calculated by differences

Table 4: Amino acids composition Chlorella vulgaris biomass Amino acidsConcentration (g/100g protein)Aspartic acid 10.5Threonine* 5.24Serine 5.08Glutamic acid 10.74Glycine 5.1Alanine 8.44Valine* 6.44Methionine* 1.5Isoleucine* 5.01Leucine* 6.84Tyrosine 5.2Phenylalanine* 4.2Histidin* 5.02Lysine* 5.6Arginine 8.2Proline 6.4NH 6.44

*: Essential amino acids

non- essential amino acids in the experimented Chlorellavulgaris biomass. So the Chlorella protein contains all ofthe essential amino acids for human growth and health[43]. However, information on the nutritive value of theprotein and the degree of availability of amino acids ofChlorella vulgaris were reported by Janczyk et al. [42].Their overall digestibility is high, which is why there is nolimitation to use dried whole Chlorella vulgarismicroalgae in foods or feeds.

In recent years, fatty acids composition in large scaleproduction of microalgae including marine algae hascreated considerable interest among researchers. This ismainly because of the health benefits of mono andpolyunsaturated fatty acids (MUFA and PUFA) that canbe found in plants including microalgae. Consumption of

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n-3 PUFAs from both seafood and plant sources may acids between different species of Chlorella, as followsreduce coronary heart disease (CHD) risk as reported by 14:0, 16:0, 16:1, 16:2,16:3, 18:0, 18:1, 18:2, 18:3. On the otherMozaffarian et al. [44] in a cohort study of 45,722 men. hand, the obtained results are unlike with that obtained byThus, many health supplement stores now sell Yusof et al. [40], who found that respective fatty acidspreparation of microalgae such as Spirulina and between different species of Chlorella, as follows 15:1,Chlorella packed in capsule or caplets, or even in food 16:0, 17:0, 18:0, 18:1, 18:2, 18:3 and 20:0. The presence of

Table 5: Fatty acid composition of oil extracted from Chlorella vulgarisbiomass (% of TFA)

Fatty acid Name Area (%)C Myristic 1.8514:0

C Palmitic 52.5616:0

C Heptadecanoic 15.8817:1

C Stearic 8.8318:0

C Oleic 5.4218:1

C Linoleic 6.5618:2

C Linolenic 8.8718:3

TSFA - 63.24TUSFA - 36.73TSFA : total saturated fatty acids.TUSFA: total unsaturated fatty acids.

and beverages known to have therapeutic values intreating hypercholesterolemia, hyperlipidaemia andatherosclerosis [45, 46].

Fatty acids composition of oil extracted fromChlorella vulgaris biomass are presented in Table 5.As expected the studied oil had elevated amount of totalsaturated fatty acids (63.24%). This oil had superiorcontent in palmitic acid; its percentage was 52.56%,followed by stearic acid (8.83%). It could be noticed thatthe most predominant unsaturated fatty acids washepatadecanoic (C17:1), its percentage was 15.88%.While, the omega 3 fatty acids linolenic in the secondorder having a percentage of 8.87%, followed bylinoleic (6.56%) the omega 6 fatty acid, then themono-unsaturated fatty acid oleic (5.42%). These findingin accordance with that found by Petkov and Garcia [47],which the palmitic acid was the major fatty acid in theirChlorella vulgaris biomass. It can be noticed that neitherfatty acid containing four double bonds, nor any with 20carbon atoms were observed. Present results show thatChlorella has quite a simple qualitative fatty acidcomposition compared to almost all green algae.However, saturated fatty acids (SFA), monounsaturatedfatty acids (MUFA) and polyunsaturated fatty acids(PUFA) displayed a significant interactive effect ofgrowth modes.

The results of fatty acids composition ofexperimented Chlorella vulgaris biomass presented inTable 5 are in agreement with those reported by Petkovand Garcia [47] and Liu et al. [48],who found that fatty

fatty acids with odd number of carbon atoms 17:1 is a firmproof that the algal culture is contaminated with bacteriaas mentioned by Petkov and Garcia [47]. Carbohydrates inChlorella vulgaris biomass can be found in the form ofstarch, glucose, sugars and other polysaccharides asmentioned by Hadj-Romdhane et al. [49]. Chlorellavulgaris biomass also represent a valuable source ofnearly all essential vitamins (e.g., A, B1, B2, B6, B12, C, E,nicotinate, biotin, folic acid and pantothenic acid) and agood source of Ca, K, Mg and Zn as reported by Yusof etal.[40]. This microalga is also rich in pigments likechlorophyll (0.5% to 1% of dry weight), carotenoids(0.1% to 0.2% of dry weight (on average) and up to 14%of dry weight for â-carotene of Dunaliella) andphycobiliproteins. Gouveia et al. [23] used the drybiomass obtained from stressed cells of Chlorellavulgaris (rich in carotenoids pigments) in animal feed,instead of the commercial synthetic pigment and stronglysuggested that yolk pigmentation was comparable to thatobtained using commercial pigments. Therefore,Chlorella vulgaris biomass is able to enhance thenutritional content of conventional food preparations andhence, to positively affect the health of humans, this isdue to their original chemical composition.

Chemical Composition of Ch A: Table 6 shows thechemical composition of Ch A treatments. It is interestingto note that both ingredients i.e., milk protein bases(acid casein) and Chlorella vulgaris biomass exhibitedsignificant albeit small effects on the chemicalcomposition of cheese analogues. There were significantdifferences between the control and only cheese analogueenhanced with 3% Chlorella vulgaris biomass in all thechemical components (moisture, fat, carbohydrate and saltcontent) except the ash content, while it were notsignificant between the cheese analogues themselves.These differences between Ch A treatments reflecteddifferences between formulations.

The main effects on chemical composition valueswere associated with the different milk protein base type;products made from acid curd had a higher protein andlower salt content and pH than that made from normalcheeses. Ch As are in agreement with those reported byMuir et al.[50], who found that the total solids and protein

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contents were higher in cheese analogues than thecontrol, while the fat and ash contents and pH valueswere lower in cheese prepared with acid casein than thecontrol. The same trend was also mentioned by Cunhaet al. [30], who reported that the analogue cheeses werehigher in protein and lower in salt content and pH valuesthan control. On the other hand, addition of the algal

Table 6: Changes in gross chemical composition (%) of processed cheese analogues enhanced with Chlorella vulgaris biomass.Ratios of Chlorella vulgaris biomass (%)------------------------------------------------------------------------------------------------------------------------------------------------

Chemical composition (%) Control 1 2 3Total solids 44.86 45.25 45.66 45.91b ab ab a

Fat/ dry matter 50.16 49.72 48.53 47.92a a ab b

Protein 13.56 14.38 14.49 14.701 b ab ab a

Carbohydrates 2.90 3.95 3.91 4.85 b a a a

Ash 4.36 3.60 3.74 3.76 a a a a

Salt in moisture 3.75 2.35 2.20 2.18 a ab b b

Fiber ND 1.18 2.42 3.662 c b a

pH 5.80 5.42 5.40 5.39 a b b b

Protein% - N × 6.38. Not determined.1 2

biomass had insignificant effects on protein, resulted in analogues that were clearly dissimilar in somecarbohydrates and fiber contents in Ch A treatments. textural attributes, especially firmness (Fig. 1). TreatmentsIt could be due to the small proportions of biomass added with high moisture content and pH around 5.70 (control)to the Ch A and these increases are a logical consequence were in general softer, while those with lower moistureof the chemical composition of Chlorella vulgaris and pH values, around 5.40 were firmer and easier tobiomass (Table 3). The pH, moisture, fat and salt contents handle (Fig. 1). The decrease in firmness caused by thewere decreased in the Ch As enhanced with biomass by increase in the moisture content of the treatments wasincreasing of the ratio of Chlorella vulgaris biomass to expected. It occurs due to the greater hydration and3%. On the contrary, protein, carbohydrates and fiber consequent weakening of the casein network [51].contents were increased by the high ratios of added Similar behavior was reported by Lawrence et al. [52] andbiomass (2 and 3%) according to the high content of Tunick et al. [53] for natural cheeses and by Fox et al. [54]these components in the Chlorella vulgaris biomass for processed cheese products. On the other hand,(Table 6). These obtained results are in the same line with Solowiej [55] observed that hardness of the processedthe results obtained by Fradique et al. [41], who found cheese analogues obtained only on the base of acidthat pasta prepared with Chlorella vulgaris and casein was very high at pH 4.5–5.0; however it decreasedSpirulina maxima presented a chemical composition significantly with an increase of pH. Addition of microalgaricher than the control pasta, namely in protein, total fat resulted in a significant (P<0.05) increase in the Ch Asand ash contents. firmness in comparison with the control sample (Fig.1).

Physical Properties of Ch As results in general tendency for an increase in firmness.Firmness Values: The compositional differences in These results evidence the positive effect of the alga inthe experimental Ch As (Table 6) were in line with the the cheese structure protection. This can be related to theexpected differences from the formulations used and fact that Chlorella vulgaris biomass has a high protein

Furthermore, raising biomass concentration (1–3.0%)

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Fig. 1: Penterometer reading (mm) of processed cheese analogues enhanced with Chlorella vulgaris biomass

Fig. 2: Oil separation index (%) of processed cheese analogs enhanced with Chlorella vulgaris biomass

Fig. 3: Melting index (%) of processed cheese analogues enhanced with Chlorella vulgaris biomass

content (>50%) [8]. The microalgae protein and protein in the resultant processed cheese emulsion. Also,carbohydrate molecules can also play an important role on many factors can affect oil separation, such as type andthe water absorption process, which promotes the amount of used raw materials in the base formula, degreeincrease of cheese firmness, as was observed by of creaming action, cooking time and temperature, theRaymundo et al. [27]. However, the obtained experimental type of emulsifying salt used and pH value in the finalresults are in agreement with the results of Fradique product etc [38]. As shown in Fig. 2, a marked significantet al. [41], who reported that the addition of Chlorella difference (p<0.05) was observed in the oil separationvulgaris biomass (0.5 -2%) resulted in a significant indexes between control and Ch A treatments.increase in the raw pasta firmness. By the same way, Batches made with acid curd enhanced with algal biomassGouveia et al. [8] found that the firmness of the biscuits showed lower oil separation indexes than the control one.increased linearly and significantly with Chlorella This may be attributed to that the control samples hadvulgaris biomass content (0.5 -3%). higher fat content and lower protein content than other

Oil Separation Index: Oil separation indexes of Ch As increased, the oil separation indexes of Ch As were moremade by replacing the hard cheeses in the base blend with decreased. As mentioned before, the addition ofacid casein curd enhanced with Chlorella vulgaris Chlorella vulgaris biomass increased the protein andbiomass at ratios of 1, 2 and 3% when fresh & after 1, 2 carbohydrates contents and decreased the fat in dryand 3 months of cold storage at 7°C are presented in matter, so the resultant emulsion for Ch As were moreFig. 2. The oil index depends on the state of the fat and stable than the control. These results are in agreement

formulas. Also, when the levels of the added biomass

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with the results of Awad and Salama [56], who mentioned Organoleptic Evaluation of Ch A Treatments: Sensorythat adding boiled egg to the formula of processed cheese analysis of cheeses is an important contribution to theirwould give a stronger network and leads to lower oil possible future commercialization, since it gives aseparation. Furthermore, cold storage of the samples perspective of the potential consumer’s acceptance.increased the free oil index; this may be due to the Organoleptic properties scores of resultant Ch As whenchanges in pH value and soluble nitrogen (SN) content fresh and during cold storage (7°C) are summarized induring storage. The lower pH values and higher SN Table 7. Firmness appreciation refers to the productcontent (more protein decomposition) would lead to lower resistance to attain a given deformation. The results indegree of product emulsification and higher fat leakage Table 7 revealed that the addition of Chlorella vulgaris[38]. biomass to the analogue cheese made by acid casein

Meltability Index: Figure 3 shows the relationship the softest. The difference was insignificant (P<0.05)between meltability (mm) of Ch A treatments as affected among the data, this could be attributed to the small ratiosby algal biomass when fresh & after 1 and 3 months of of microalgae biomass in the mixture. The panelistsstorage at 7°C. Melting index of Ch As made by replacing preferred the microalgae cheeses, particularly those withthe hard cheeses in the base blend with acid casein the microalgae content (2%), in comparison with the otherenhanced with 1, 2 and 3% of Chlorella vulgaris biomass microalgae samples (1 and 3% microalgae). In the samehad significantly the lowest meltability values than that time, all Ch A treatments became more firm when storedcontrol (p<0.05). On the other hand, the results indicated up to 3 months which is in accordance with the resultsthat meltability of the Ch As insignificantly decreased found by Awad et al. [38].with increasing algal biomass amount (Fig. 3). The cheese Stickiness is the work necessary to overcome themeltability showed a tendency to decrease after storage attractive forces between the surface of the food and theat 7°C for 3 months. This could be due to the changes in other materials with which the food comes in contact, it’spH and SN content of processed cheese, as mentioned by also meaning the resist separation of cheese from aAwad et al. [38]. The obtained results of meltability of Ch material it contacts [61]. All Ch A treatments wereAs are in the same trend with those of firmness (Fig. 1) nonsticky and enhanced cheese analogues with 2 and 3%and chemical composition (Table6). The progressive biomass showed very slight stickiness. This could be dueincrease in hardness and decrease in flow ability values the effect Chlorella biomass on the cheese protein(Fig. 3), at increased biomass ratio may be related to solubility. This effect may be due to the hydrolysis ofthe observed decrease in fat globule sizes. Similarly, emulsifying salts during storage causing a decreaseCavalier-Salou and Cheftel [57] found that melting ability in pH value, which hardened the cheese samples.was correlated to high pH, soft texture, high degree ofcasein dissociation and low degree of fat emulsification.Shirashoji et al. [58] also reported that high firmness andlow melting values in process cheese were associatedwith small fat globule sizes. By the same way, Gupta andReuter [59] reported that the softer body of processedcheese foods with higher moisture content might help inproviding higher meltability as f1owability improves.Moreover, Savello et al. [34] found that rennet caseincheese melted significantly more than the acid caseincheese. Otherwise, Mounsey and O’Riordan [60] notedthat imitation cheese with poor melting characteristicsis often desirable when used in products that aredeep-fat-fried.

produced the firmest cheese (Fig.1), while the control was

Table 7: Sensory evaluation of processed cheese analogues enhanced with Chlorella vulgaris biomass during storage at 7°C for 3 monthsRatios of Chlorella vulgaris biomass (%)--------------------------------------------------------------------------------

Character Assessed Storage period (month) Control 1 2 3Firmness (1-7) Fresh 6.80 6.82 6.90 6.90a a a a

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1 6.82 6.87 6.95 6.92a a a b

3 6.90 6.91 6.98 6.95a a a a

Stickiness (1-5) Fresh 5.00 4.91 4.95 4.86a a a a

1 4.93 4.86 4.90 4.52a ab ab b

3 4.93 4.79 4.81 4.43a ab ab b

Crumbliness (1-7) Fresh 7.00 6.96 6.90 6.86a a a a

1 7.00 6.90 6.92 6.82a a a a

3 7.00 6.80 6.85 6.80a a a a

Sliceability (1-5) Fresh 4.85 4.57 4.60 4.32a ab ab b

1 4.62 4.45 4.48 4.00a ab ab b

3 4.38 3.78 4.25 3.56a b a b

Acceptability (1-7) Fresh 7.00 6.80 6.95 6.77a a a a

1 6.94 6.75 6.92 6.63a a a a

3 6.92 6.60 6.90 6.40a ab a b

Means not followed by the same lower case letter in each row are significantly different (p 0.05). a, b, c

These obtained results are in the same trend of the The flavor was found to be the most importantobtained firmness results and also are in agreement with attribute that affect the acceptability of a cheese analoguethose obtained by Pereira et al. [62], who mentioned that containing chlorella vulgaris biomass in different ratios.cheeses with lower moisture content were, in general, However, all analogues treatments scored positively (>6)firmer, curdier and less sticky than cheeses with higher revealing a good acceptance by the panelists. There weremoisture content. Products with intermediate moisture no significant differences detected by the panelistscontent resulted, in general, intermediate scores for these between analogous with microalgae biomass and theattributes. control. Although some individuals detected a strange

The scores of stickiness decreased throughout the flavor in the batches prepared with 2.0 and 3% ofentire storage period, this suggesting that the cheese Chlorella vulgaris biomass. Storage of cheese samplesmatrix became sticky during storage as a resulted of lowered the acceptability and the cheese enhanced withincreased mobility during storage as observed by Awad 3% chlorella biomass showed significantly loweret al. [38]. Crumbliness refers to the strength of the acceptability after 3 months of cold storage. From theinternal bonds making up the body of the product. sensory evaluation results, it could be concluded that theThere was no crumbliness detected in fresh cheese addition approximately 2% Chlorella vulgaris biomass insamples except the cheese enhanced with 3% Chlorella the Ch A did not have significant effect on the overallbiomass that was insignificant slightly crumbly. acceptability score of it and in the same time introducedThis could be due to the low pH value (Table 6) in the a new healthy alternative processed cheese analogue.sample, which makes the protein more crumbly. The sameobservation was also noticed after 1 month of storage. CONCLUSIONAfter 3 months, slight crumbliness was detected in therest of all treatments. This change is mainly due to the Significant attention has recently been drawn to thedecrease in pH values that occurred during the storage use of microalgae for developing functional food, asperiod [38]. Sliceability is the ability of the product to cut microalgae produce a great variety of nutrients that areinto slice. The Ch A treatments showed very good essential for human health. Chlorella vulgaris has beensliceability being significantly good in control and named green healthy food by FAO, rich in nutrients, suchanalogue cheese enhanced with 2% Chlorella vulgaris as proteins, total lipid, total carbohydrate, minerals,biomass. Analogue enhanced with 3% algae biomass dietary fibers, antioxidants and vitamins. Chlorellashowed a slightly breakable texture and did not give good vulgaris biomass provides a functional ingredients forcheese slice. The sliceability was related to the cheese feed additive, pharmaceutical and nutraceutical purposes.firmness and decreased during storage. Ch A enhanced A novel processed cheese analogue was successfullywith 3% chlorella biomass showed significantly decrease produced by adding microalgae biomass to cheese blend.in sliceability. General acceptability of cheese is Ch A treatments prepared with Chlorella vulgarisconcerned with texture, odor and flavor attributes. presented a chemical composition richer than the

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control, namely in protein, carbohydrates, fiber and ash. University of Ireland, Galway. Accessed through:The physical quality of analogues was improved byincluding microalgae, the textural characteristics of theresultants, namely firmness, were positively affected bythe inclusion of microalgae, when compared to the controlsamples. The increase of analogue firmness may berelated to the addition of components rich in protein that,probably have a significant influence in the structure ofthe cheese network. In the same time, the resultantemulsion Ch As was more stable than the control, bygiving a stronger network and leads to lower oilseparation. The meltability of Ch A enhanced bychlorella was lower than control one, which meaning thatthe meltability of Ch As could be manipulated by theaddition of algal biomass. Microalgae-enriched Ch As wassensorial well accepted by the panelists. So, it could besay that addition approximately 2% Chlorella vulgarisbiomass as natural healthy ingredient can introduce a newacceptable healthy alternative processed cheeseanalogue.

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