A. S. Akalin

Effects of Inulin and Oligofructose on the Rheological Characteristics and Probiotic Culture Survival in Low-Fat Probiotic Ice Cream

The effects of supplementation of oligofructose or inulin on the rheological characteristics and survival of Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 in low-fat ice cream stored at -18 degrees C for 90 d were studied. Addition of oligofructose or inulin to ice cream mix significantly increased apparent viscosity and overrun and developed the melting properties in ice cream during storage (P < 0.05). However, the highest increase in firmness, the lowest change in melting properties, and the longest 1st dripping time were obtained in probiotic ice cream containing inulin (P < 0.05). Some textural properties have also improved especially by the end of storage. Freezing process caused a significant decrease in the viability of Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 (P < 0.05). Oligofructose significantly improved the viability of L. acidophilus La-5 and B. animalis Bb-12 in ice cream mix (P < 0.05). Although the viable numbers for both bacteria decreased throughout the storage, the minimum level of 10(6) CFU/g was maintained for B. animalis Bb-12 in only ice cream with oligofructose during storage.

Microstructural, textural, and sensory characteristics of probiotic yogurts fortified with sodium calcium caseinate or whey protein concentrate

The influence of milk protein-based ingredients on the textural characteristics, sensory properties, and microstructure of probiotic yogurt during a refrigerated storage period of 28 d was studied. Milk was fortified with 2% (wt/vol) skim milk powder as control, 2% (wt/vol) sodium calcium caseinate (SCaCN), 2% (wt/vol) whey protein concentrate (WPC) or a blend of 1% (wt/vol) SCaCN and 1% (wt/vol) WPC. A commercial yogurt starter culture and Bifidobacterium lactis Bb12 as probiotic bacteria were used for the production. The fortification with SCaCN improved the firmness and adhesiveness. Higher values of viscosity were also obtained in probiotic yogurts with SCaCN during storage. However, WPC enhanced water-holding capacity more than the caseinate. Addition of SCaCN resulted in a coarse, smooth, and more compact protein network; however, WPC gave finer and bunched structures in the scanning electron microscopy micrographs. The use of SCaCN decreased texture scores in probiotic yogurt; probably due to the lower water-holding capacity and higher syneresis values in the caseinate-added yogurt sample. Therefore, the textural characteristics of probiotic yogurts improved depending on the ingredient variety.

Enrichment of probiotic ice cream with different dietary fibers: Structural characteristics and culture viability

This study evaluated the effect of 5 dietary fibers (apple, orange, oat, bamboo, and wheat) on the physicochemical, rheological, and textural characteristics; sensory properties; and culture viability of probiotic ice cream stored at -18°C for 180 d. The presence of orange and apple fibers increased the titratable acidity, decreased the lightness (color) value of the ice creams, and enhanced the red and yellow coloration. Compared with the control sample, the consistency indices and apparent viscosities of the experimental samples increased with the addition of all dietary fibers except oat fiber. The highest viscosity was obtained in the sample fortified with apple fiber, whereas the ice cream containing orange fiber showed the highest hardness after d 60 of storage. The addition of orange and apple fibers significantly increased melting resistance; however, panelists did not generally like these samples in terms of taste-flavor. All ice creams had viable counts of Lactobacillus acidophilus of ≥7 log cfu/g during storage except the samples with orange and bamboo fiber. Bifidobacterium lactis counts were also found to be >6 log cfu/g in those samples until d 150 of storage.

Effect of Supplementation with Green and Black Tea on Microbiological Characteristics, Antimicrobial and Antioxidant Activities of Drinking Yoghurt

The influence of supplementation with green and black tea on microbiological properties, antimicrobial and antioxidant activities of drinking yoghurt were investigated during 21 days of storage. The samples supplemented with 2% either green or black tea had higher viable counts of both yoghurt starter bacteria than those of infused by the ratio of 4%. Both green and black tea extracts showed antimicrobial activity on E. coli, B. cereus, S. aureus and C. albicans however this effect was detected higher in samples containing green tea. The samples added green tea extract had the highest DPPH scavenging activity when compared to those supplemented with black tea extract throughout the storage. Green tea had a superior effect than black tea in terms of total phenolic content of drinking yoghurt samples.

Yeşil ve Siyah Çay İlavesinin İçilebilir Yoğurdun Viskozitesi ve Duyusal Özellikleri Üzerine Etkisi

Siyah ve yesil cayin icilebilir yogurdun viskozitesi ve duyusal ozellikleri uzerine etkisi arastirilmistir. Calismada iki cay infuzyon konsantrasyonu (%2 ve %4) kullanilirken herhangi bir ilave yapilmayan icilebilir yogurt kontrol ornegi olarak yer almistir. En yuksek viskozite degerleri kontrol orneginde tespit edilirken cay ekstrakti ilave edilen icilebilir yogurtlar arasinda 14.gun disinda onemli bir fark bulunamamistir. %4 oraninda cay ilave edilmesi %2 orani ile kiyaslandiginda tat puanlarini olumsuz yonde etkilemistir. %2 yesil cay ile muamele edilen icilebilir yogurt kontrol ornegine benzer renk ve tekstur degerleri gostermistir. %2 siyah veya yasil cay ilave edilen orneklerde toplam kabul edilebilirlik acisindan istatistiksel olarak herhangi bir fark belirlenememistir.