Production of Functional Yogurt: Effect of Natural Antioxidant from Guava (Psidium guajava) Leaf Extract
Hamid M ZienaandAbeer M Abd Elhamid
Department of Food and Dairy Science &Technology, Faculty of Agriculture,( Damanhour) AlexandriaUniversity, 22516, Egypt.
The possibility of producing a functional yogurt from a skimmed buffalo's milk using guava (Psidium guajava) leaf extract was investigated. Methanol exhibited slightly higher extraction ability for phenolic compounds than ethanol and water. The total phenols were 894, 882 and 877μg/g powder, respectively, when extraction ratio was 1:12.Addition of water extract of guava leaf by different concentrations to a functional yogurt, showed significant changes of pH, titratable acidity during cold storage up to 5 days.The reducing activity of all samples significantly (P>0.05) decreased up to the end of storage period, while the inhibition of ascorbate autoxidation significantly increased with increasing of the amount of phenolic compounds till 300 μgphenolic components /100ml yogurt followed by a slight decrease. During storage, the average viable cell counts on MRS increased in yogurt contained guava leaf extract75 μg phenolic component /100ml from log CFU/ml 9.60 after one day to 10.17 on day 5. Notwithstanding, there was a decline in log CFU/ml on M17throughout storage.Sensory evaluation data indicated no significant differences (P>0.05) between the control and treated samples. Based on the above results, technology can be proposed for productions of a functional yogurt with water extract of guava leaf, as natural antioxidant source.
Keywords: antioxidant, guava leaf, chemical, microbial, sensory properties, yogurt.
Published In:Journal of Agricultural and Environmental Sciences, (2009)8(1):102-116.
ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Effects of Resistant Starch and Storage Time on Growth and Viability of Bifidobacterium and Viscosity of Skim Milk Probiotic Yoghurt
Abeer M Abd Elhamid
The effects of adding resistant starch on the viscosity and growth and viability of Bifidobacterium longumATCC15707 in yoghurt were investigated.Resistant starch was prepared by wet processing of commercial starch with autoclaving and cooling. The wet-processed starch was used to substitute 2 % of milk solids in skim milk yoghurt manufacture (13 %). Addition of starch, decreased significantly the pH (P<0.01) and increased the viscosity and decreased syneresis (P<0.01) of yoghurt during storage. The amylose and amylopectin contents were almost unchanged, which the resistant starch content of yoghurt increased significantly (P<0.01) during storage. Also, addition of wet -processed starch stimulated the growth of Bifidobacterium longumATCC15707 in yoghurt during storage. Addition of wet-processed starch can be recommended in the manufacture of probiotic set-yoghurt as a thickner to improve the viscosity and water holding capacity of the product and enhance the growth and viability of the added probiotic.
Key words:Resistant starch, set-yoghurt, viscosity, syneresis, Bifidobacterium longum.
Published In:Proceeding of the 11th Egyptian conference for Dairy Science and Technology, 1 – 3, November (2010), 395 – 405. Cairo – Egypt.
Using Cheese Whey in the Preparation of Fermented Beverage
Abd- Elhamid, Abeer M.
Department of Food and Dairy Science &Technology, Faculty of Agriculture (Damanhour), Alexandria University,Egypt.
The possibility of producing a natural beverage from whey which, supplemented with buffaloes, milk and starch to increase the nutritional value was investigated. Addition of starch by different concentrations to a fermented beverage, showed a significant changes of pH, titratable acidity.The pH of all samples decreased, while the titratable acidity increased significantly (P>0.01) with increasing of the amount of starch up to the level3%. During storage, the average viable cell counts on MRS in fermented beverage had 25% buffaloes, milk : 75% whey : 3 % starch was log CFU/ml 9.26 after one day and 9.28 on day 7. Notwithstanding, there was a slight decline in log CFU/ml on M17throughout storage. The viscosity of all samples increased gradually by increase concentration of starch but significantly (P>0.01) up to the end of storage period. Beverages of accepted sensory properties were obtained by mixing 75 % buffaloes, milk: 25 % whey: 2 % starch atP>0.01. Based on the above results, technology can be proposed for productions of a natural beverage have starch as natural hydrocolloids source.
Key wordsCheese Whey, Fermented Beverage, starch, Bifidobacterium longum.
Published In:Egyptian Journal of Dairy Science, (2010)38(2):201-210.
ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Production of Functional Kariesh Cheese: Effect of Natural Antioxidant from Guava (Psidium guajava) Leaf Extract
Abd- Elhamid Abeer M.
Department of Food and Dairy Science &Technology, Faculty of Agriculture, Damanhour University,Egypt.
The possibility of producing a functional kariesh cheese from a cow's skim milk using guava (Psidium guajava) leaf extract was investigated. Methanol exhibited slightly higher extraction ability for phenolic compounds than ethanol and water. The total phenols were 894, 882 and 877μg/g powder, respectively, when extraction ratio was 1:12. Addition of water extract of guava leaf by different concentrations to a functional Kariesh cheese, showed significant changes of pH during cold storage up to 14 days.The reducing activity of all samples significantly (P<0.01) decreased up to the end of storage period, while the inhibition of ascorbate autoxidation significantly increased with increasing of the amount of phenolic compounds till 300 μgphenolic components /100g Kariesh cheesefollowed by a decrease. After 7 days of storage, the log CFU/g of Kariesh cheesecontained guava leaf extract375 μg phenolic component /100gKariesh cheesewere 8.94, while thea functional kariesh cheesecontained guava leaf extract75 μg phenolic component /100g Kariesh cheese were 8.66on Standard Plate Count Agar medium. Sensory evaluation data indicated that 225 µgphenolic components /100g Kariesh cheeseas the limit that can be added without adversely affecting sensory properties and storage ability. Based on the above results, technology can be proposed for productions of a functional Kariesh cheese with water extract of guava leaf, as natural antioxidant source.
Keywords: Functional Kariesh cheese; guava leaf extract; antioxidant, phenolic compounds; ascorbate autoxidation.
Published In:Egyptian Journal of Dairy Science, (2011)39:101-110.
ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Production ofFunctional Yoghurt by Microen-capsulation ofLactococcus lactis ssp. lactis and Raffinose
Abeer M. Abd-Elhamid
Department of Food and Dairy Science & Technology, Faculty of Agriculture, Damanhour University, Damanhour, 22516, Egypt.
ACTOCOCCUSlactis ssp. lactis and raffinose were microencapsulated with rennet gelation of milk proteins. The effects of microencapsulation on the changes in survival rate of Lactococcus lactis ssp. lactis under simulated gastrointestinal conditions were estimated. The bile tolerance of Lactococcus lactis ssp. lactis at different concentrations of bile was studied. The survivability of encapsulated Lactococcus lactis ssp. lactis and the remained raffinose in yoghurt during 4 weeks of cold storage were determined. The results showed that, the survival of encapsulated Lactococcus lactis ssp. lactis in bile solution was significantly enhanced (P< 0.01) compared to the freeLactococcus lactis ssp. lactis. Furthermore, the study demonstrated that microencapsulation using rennet gelation of milk proteins could increase the survival ofLactococcus lactis ssp. lactis in simulated gastric conditions. EncapsulatedLactococcus lactis ssp. lactis had a positive effect in the survival capacity of Lactococcus lactis ssp. lactis in yoghurt during cold storage as compared to free Lactococcus lactis ssp. lactis. In addition, the capsules made from rennet gelation of milk proteins provided a significant enhanced protection to the raffinose during fermentation period and cold storage.
Keywords: Functional Yoghurt; Lactococcus lactisssp. lactis; Microen-capsulation, raffinose.
Published In:Egyptian Journal of Food Science. (2011)39, pp. 107 – 118.
Production of Functional Kariesh Cheese by Microencapsulation of
Bifidobacterium adolescentis ATCC 15704
A.M. Abd-Elhamid
Department of Food and Dairy Science andTechnology, Faculty of Agriculture, Damanhour
University, Damanhour, 22516, Egypt
Bifidobacterium adolescentis ATCC 15704 was microencapsulated with rennet gelation of milk proteins. Encapsulated and free Bifidobacterium adolescentis ATCC 15704 under simulated gastrointestinal conditions and bile tolerance were estimated. The survivability of encapsulated Bifidobacterium adolescentis ATCC 15704 and the changes of organic acids in Kariesh cheese during 2 weeks of cold storage were determined. The study demonstrated that microencapsulation using rennet gelation of milk proteins increased the survival of Bifidobacterium adolescentis ATCC 15704 in simulated gastric conditions. Furthermore, the results showed that, the survival of encapsulated Bifidobacterium adolescentis ATCC 15704 in bile solution was significantly enhanced (p<0.05) compared to the free Bifidobacterium adolescentis ATCC 15704. Microencapsulation protected Bifidobacterium adolescentis ATCC 15704 in Kariesh cheese during cold storage as compared to free Bifidobacterium adolescentis ATCC 15704. In addition, the capsules made from rennet gelation of milk proteins had a positive effect in organic acids during cold storage.
Keywords:Bifidobacterium, bile tolerance, microencapsulation, organic acids, Kariesh cheese
Published In:Advance Journal of Food Science and Technology (2012)4(2): 112-117.
ـــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Improving the textural properties of Egyptian kariesh
cheese by addition of hydrocolloids
MOHAMED KORISH and ABEER M ABD ELHAMID*
Department of Food and Dairy Science &Technology, Faculty of Agriculture, Damanhour University, Damanhour 22516,
Egypt
In this study, the effect of addition of hydrocolloids (commercial pectin, citrus pectin or carboxymethylcellulose) to Egyptian Kariesh cheese at 0.2, 0.4 and 0.6% (w⁄ w) on chemical composition, yield, rheological and sensory characteristics was investigated. The results revealed that the addition of hydrocolloids increased moisture content and yield values of Kariesh cheeses compared with control. Protein, salt and ash content decreased with increasing hydrocolloids levels. Rheological characteristics (hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness, resilience) were significantly lower in cheeses made with hydrocolloids. Kariesh cheese made with 0.4% w⁄w commercial pectin and 0.6% w⁄w carboxymethylcellulose recorded the highest scores for sensory attributes.
Keywords:Hydrocolloids, Commercial pectin, Citrus pectin, Carboxymethylcellulose, Rheological and sensory characteristics, Kariesh cheeses.
Published In:International Journal of Dairy Technology (2012)65(2):237-242.
ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Quality attributes of stirred Zabadycontaining freeze-dried strawberry coated with acacia film
Abeer M Abd Elhamid*and Hamid M Ziena
Department of Food and Dairy Science &Technology, Faculty of Agriculture, Damanhour University, Damanhour, 22516, Egypt.
Strawberry Zabady was made by adding freeze-dried (FD)strawberry after rehydration in different of sucrose syrups (30, 40, 50%W/W for 30 min) with or without coatingwith acacia film. Changes in pH, syneresis, and Lactobacillus delbrueckiisubsp. bulgaricus, Streptococcus thermophilus, coliforms, and yeasts and molds counts, total sugars and sensory properties of Zabady from different treatments were assessed when fresh and during refrigerated storage for 21 days. Zabady made from FD strawberry covered with acacia film developed less acidity and syneresis during cold storage. The counts of Lb. bulgaricus and Str. thermophilus were less in Zabadymade with FD strawberry covered with acacia film than that without. Also, coliforms and yeasts and molds were not detected in all treatments. Data for organoleptic scoring revealed low score for Zabadymade from FD strawberryand rehydrated in 30 and 40 % sucrose syrups, while that rehydrated in 50% sucrose syrup and covered with acacia film gained high scores and was the most acceptable one.
Keyword:freeze-dried strawberry, acacia, chemical, microbial, sensory properties, Zabady
Published In: Egyptian Journal of Dairy Science, Vol. 40(2) pp. 111-119, December2012.
Isolation and Characterization of Lactic Acid Bacteria from Egyptian Laban Rayeb and the Use of Some Isolated Cultures in the Preparation of Laban Rayeb
Abd- Elhamid, Abeer M;٭ Khattab, A.A.; El– Ghannam, M.S. and Ziena, H.M.
٭
٭Department of Food and Dairy Sci.&Tech., Fac.,of Agric.(Damanhour).Alexandria Univ.Egypt.
Department Dairy Scienc & Technology. Faculty of Agric. El- Shatby, Alexandria Univ, Egypt.
Lactic acid bacteria were isolated (200 colonies) and characterized from 56 samples of traditionalLaban Rayeb samples. The acid production and antagonism of the isolated cultures were evaluated, and different combinations of these isolates were used in the preparation of Laban Rayeb-like product. Five of the isolated cultures (Lactococcus lactisADD184, Streptococcus thermophilus ADD197, Lactobacillus casie ADD210, Entercoccus faecalis ADD178 andLactobacillus delbrueckiilactisADD299) and known commercial strains (Streptococcus thermophillus CNRZ703 , Lactobacillus casei CNRZ1222 , Lactobacillus delbrueckiissp. bulgaricus CNRZ8 and Bifidobacterium bifidum ATCC11147)were used in making six combination of lactic acid starter in the preparationLaban Rayeb-like product usingfresh buffaloe’s skim milk. The changes in CFU/ml of LAB, Bifidobacterium, moulds and yeasts in the prepared products were followed over 5 days of storage. Also, the treatments were analysed for their chemical composition (pH, acidity, lactose, soluble N, acetaldehyde and volatile fatty acids) and evaluated for sensory attributes.Laban Rayeb-like product was ranked the highest scores for sensory attributes and was comparable to the traditional product. Therefore, it is recommended using this mixed culture in the manufacture of Laban Rayeb-like product.
Keywords:Laban Rayeb, lactic acid bacteria, microbiological quality, chemical composition, sensory attributes.
Published In:Egyptian Journal of Dairy Science, .(2009) 37:227-236.
ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Chemical and Microbiological Content of Laban Rayeb
Fifty six Laban Rayeb samples were collected from seven different districts of Behera Governorate. They were analyzed for their chemical and microbiological composition. The averages values of pH, acidity, fat, total solids, lactose %, total nitrogen, TVFA and acetaldehyde were 4.29, 1.08%, 1.68%, 10.51%, 3.32% 0.503%, 38.99 ml NaOH 0.1N /100 gm, and 37.76 ppm, during summer, respectively. Corresponding values for winter were 4.47, 0.91%, 0.54%, 10.04%, 3.96%, 0.565%, 28.65ml NaOH 0.1N /100 gm and 24.24 ppm, respectively.Concerning the microbiological content, marked differences were noticed between summer and winter’s seasons specially for Lactic acid bacteria and count of coli form group. Staphylococcus aureus was detected in about 30% of the samples collected in winter while none of the summer samples contained this organism.
Published In:Egyptian Journal of Dairy Science, (2008)36:221-22
،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،،
In VitroEffects of pH and Bile Salts on the Viability of Some Lactic Acid Bacterial Strains
Abd- Elhamid, Abeer M;٭ Khattab, A.A and Ziena, H.M.
Five strains of lactic acid bacteria were examined for their surviving in artificial juice like intestinal at certain pH values, all strains exhibited significant decrease in the log10 CFU/ml as the pH valuedecreases for example the log10 CFU/ml of Lb. rhamnosus NRRLB–1934 at zero time was 7.73 decreased to 7.23 and 7.50 at pH 1.5 and 2.5, respectively, after 1h of incubation at 37ºC at P<0.05. Prolongation time to 2hrs., decreased the log10 CFU/ml to 6.79 and 7.43, respectively. All the tested strains i.e. Lb. casei subsp. casei NRRLB- 1922T, Lb. paracasei subsp. paracasei NRRLB-4564, Lb. acidophilus NRRLB–2092 and Lb. rhamnosus NRRLB-1934 exhibited the same conclusion that decreasing the pH reduces the log10 CFU/ml of the tested strains.Moreover, Lb. rhamnosusNRRLB-1934 and Lb. acidophilus NRRLB–2092 were found to be more tolerance at pH 1.5 in comparison with the other strains. Lb. acidophilus NRRLB-1910 andLb. paracasei subsp.paracasei NRRLB–4564 were the lowest tolerance for pH 1.5 and 2.5 after 3hrs., of incubation ,however the remained alive cells were over 77% of the original bacterial cells count. Also the viability of tested strains in different bile salt % were determined, the log10 CFU/ml of all the tested strains was decreased significantly at P<0.05 as the bile salts% in MRS broth increased. There is significant difference between the tested strains for their bile salts tolerance either at 0.15 and 0.30% bile salts concentrations after 48hrs., except Lb. rhamnosus NRRLB–1934 and Lb. casei subsp. casei NRRLB-1922T. The most resistant strain for 0.3% bile salt concentration was Lb. casei subsp.casei NRRLB-1922T after 24 hrs.
Published In:Proceeding of the 6thBio Vision Alexandria 2010 International Conference, 11 – 15, April, 2010. Alexandria – Egypt.
abeer.khalif@danamhour.edu.eg