In this study, some properties of probiotic yoghurt ice cream supplemented with carob extract and whey powder and viability of L. acidophilus and Bifidobacterium BB-12 on ice-cream were investigated. For this purpose 6 different ice cream was produced with different ratios whey powder and carob extract. The viable probiotic bacteria counts were determined on 1 st, 7 th, 30 th, 60 th and 90 th days of storage. Addition of carob extract and whey powder significantly affected all properties of ice-creams. Results showed that the most positive effect on physical, sensory and microbiological properties was observed on sample D which produced with 1% carob extract and 1% whey powder addition.
Due to their attributed health benefits, probiotic bacteria (such as L. acidophilus and/or Bifidobacteria) have been increasingly applied in the dairy industry during the past two decades and are consumed at appropriate levels as part of a balanced diet. Many studies indicated that ice cream was an excellent vehichle for probiotic bacteria when compared to fermented dairy products [
Carob (Ceratonia siliqua L.) is an evergreen tree belonging to the Leguminosae family, widely cultivated in the Mediterranean region, mainly Spain, Italy, Portugal, and Morocco [
Whey powder contains amino acids such as cysteine, methionine, threonine. Dave and Shah [
The objective of this study was to improve the survival of the cells during freezing in probiotic ice cream by adding carob extract and whey powder and to determine their survival immediately after freezing and during storage. Furthermore, the effects of carob extract and whey powder levels on the physical and sensory characteristics of the probiotic ice-cream were also examined.
The non-fat milk powder (96% total solids) (Pınar Dairy, Turkey), cream (35% fat) (Tat Can Industry. A.S. SEK Plant, Turkey) and Lactobacillus acidophilus LA-5 (L. acidophilus) and Bifidobacterium animalis subsp. lactis BB-12 (Bifidobacterium BB-12) (Peyma-Chr. Hansen, Turkey) were used for ice cream production. Carrageenan (E 407), Guar gum (E 412), Xanthan gum (E 415) and Sodium alginate (E 401) (Sosa Ingredients, S.L. Ctra de Granera, Spain) were used as stabilizers. Lecithin was used as emulsifier and was obtained from Sosa Ingredients (S.L. Ctra de Granera, Spain). Sucrose (100% TS) was used as a sweetener, and vanilla was added for aroma development. Carob extract and whey powder were obtained from Yeşil Deva and Maybi (Tekirdag, Turkey), respectively. All of the other used reagents were of analytical grade.
Ice cream was formulated with the following composition (percentage by weight) such that it had 34% - 35% total solids for a total batch of 5 kg: 11% non-fat total milk solid, 18% sugar, 5% fat, 0.8% stabilizers and 0.3% emulsifier. The mixes contain different ratios of whey powder and carob extracts (A: 0.5% whey powder, B: 1% whey powder, C: 0.5% whey powder + 1% carob extract, D: 1% whey powder + 1% carob extract, E: 1% carob extract, F: control). The milk and cream (35% fat) were mixed and temperature brought to 45˚C, the skim milk powder, sugar, whey powder and carob extract, plus water, were added and pasteurized at 85˚C for 1 min. This mixes were homogenised at 85˚C while stil hot, and allowed to cool to 40˚C. They inoculated with probiotic fermented milk at a rate of 5% and incubated at 37˚C until pH 5.5 was attained. The probiotic ice-cream was produced by using a vertical freezing machine of 6 kg capacity (Uğur, Nazilli, Turkey). The partially frozen mix was packaged in 50, 100 and 200 mL cups and stored at −18˚C. Manufacturing stages for the production of probiotic ice-cream is shown in
Bacterial counts were determined fermented milk, immediately after mixing, and after freezing, at 7, 30, 60 and 90 days of storage at −18˚C. Fermented milk, mix and ice-cream samples (10 g) were decimally diluted in 100 mL sterile peptone water (0.1%) and 1 mL aliquot dilutions were poured onto plates of the various selective and
differential agars in triplicate. L. acidophilus and Bifidobacterium BB-12 were incubated by using MRS with sorbitol and MRS-NNLP agar, respectively [
The pH of the produced ice cream samples was measured using a digital pH-meter and titratable acidity was determined according to the Soxhlet Henkel method [
The overrun of the final product was determined formulas follows [
Overrun = (Weight of unit mix-weight of equal volume of ice cream)/(weight of equal volume of ice cream) * 100
First dripping times were measured according to Güven and Karaca [
Sensory analysis of the ice-cream samples was assessed by ten untrained panellists. A 10 point hedonic scale was used to evaluate coldness, firmness, viscosity, smoothness, colour and appearance, mouth coating, flavour, taste and general acceptability (1 = strongly unacceptable, 10 = very good) as described by Aime et al. [
Statistical analysis of data via one-way analysis of variance (ANOVA) was performed to check the significance of differences at p < 0.01 using SPSS Version5.0 (SPSS Inc. Chicago, IL, USA). Statistically different groups were determined by the LSD (Least Significant Difference) test [
L.acidophilus and Bifidobacterium BB-12 counts of fermented milks were 8.11 and 8.95 log cfu g−1. During freezing, the numbers of viable L. acidophilus and Bifidobacterium BB-12 decreased by 0.71 - 0.99 and 1.32 - 1.73 log unit, respectively. It could be related to the result of freezing, is likely due to the freeze injury of cells, leading eventually to the death of cells. However, the mechanical stresses of the mixing and freezing
process and also the incorporation of oxygen into the mix, may have resulted in a further decrease in bacterial count. Previous reports show that oxigen toxicity caused by the incorporation of air during the ice cream production may seriously affect the growth of anaerobic bacteria [
L. acidophilus and Bifidobacterium BB-12 decreased in all samples during 90 days storage period (p < 0.01). The decrease in the numbers of L. acidophilus and Bifidobacterium BB-12 in samples supplemented with carob extract and whey powder was less than those of the control and the other samples. The viable L. acidophilus counts at the end of 90 days storage period was under 106 cfu g−1 in all the samples, however the viable Bifidobacterium BB-12 counts at the end of 90 days storage period was above the samples supplemented with 1% carob extract and whey powder (Sample D). Akin [
The some chemical properties of probiotic ice-creams were given in
Samples* | pH | Acidity (%L.A) | Dry Matter (%) |
---|---|---|---|
A | 4.97 ± 0.065a | 1.071 ± 0.018ab | 31.23 ± 0.14a |
B | 4.93 ± 0.005ab | 1.148 ± 0.005bc | 31.61 ± 0.11ab |
C | 4.94 ± 0.015ab | 1.116 ± 0.009bc | 32.73 ± 0.08c |
D | 4.91 ± 0.025ab | 1.152 ± 0.023c | 32.84 ± 0.07c |
E | 4.97 ± 0.040ab | 1.112 ± 0.009bc | 31.97 ± 0.03b |
F | 5.03 ± 0.040b | 1.022 ± 0.014a | 31.11 ± 0.11a |
*A: 0.5% whey powder. B: 1% whey powder. C: 0.5% whey powder +1% carob extract. D: 1% whey powder +1% carob extract. E: 1% carob extract. F: Control; **a,b,c,Means in the same column followed by different letters were significantly different (p < 0.01).
The physical properties of ice-creams are shown in
The samples supplemented with carob extract and whey powder had higher viscosity than control samples due to the high water binding capacity of them. As known carob gum is used as a stabilizer. On the other hand, whey proteins had high water holding capacity [
The meltdown characteristics are important quality parameters of probiotic ice cream [
Samples* | Viscosity (cP) | Overrun (%) | First Dripping Time (s) | Melting Rate (%) | ||
---|---|---|---|---|---|---|
30th min | 60th min | 90th min | ||||
A | 8196 ± 8b | 20.71 ± 0.885ab | 2089.5 ± 150.5ab | − | 84.17 ± 0.080abc | 97.99 ± 0.05a |
B | 8252 ± 64b | 20.83 ± 1.050ab | 2252.5 ± 145.5ab | − | 83.42 ± 0.950ab | 96.36 ± 0.04a |
C | 8390 ± 46b | 22.56 ± 1.300ab | 2451.5 ± 106.5ab | − | 83.81 ± 0.005abc | 97.09 ± 0.55a |
D | 8594 ± 66b | 22.66 ± 1.120b | 2560 ± 72.0b | − | 80.68 ± 1.00a | 95.98 ± 0.54a |
E | 8062 ± 26b | 20.95 ± 0.985b | 2094 ± 36.0ab | − | 85.79 ± 0.990bc | 98.14 ± 0.18a |
F | 6518 ± 234a | 17.04 ± 0.090a | 1969.5 ± 5.5a | − | 87.01 ± 0.590c | 98.26 ± 0.95a |
*A: 0.5% whey powder. B: 1% whey powder. C: 0.5% whey powder +1% carob extract. D: 1% whey powder +1% carob extract. E: 1% carob extract. F: Control; **a,b,cMeans in the same column followed by different letters were significantly different (p < 0.01).
Addition of carob extract and whey powder had significant effect on the tested sensory characteristics (
The lowest coldness was in the samples with 1% carob extract and whey powder. Coldness is related to large ice particles. When the water content increase, the larger ice particles formed in ice cream and the sensation coldness is intensify [
Control samples had the highest smoothness score. There is a decrease in smoothness score with increasing the whey powder addition. It could be related lactose content of whey powder. As known lactose caused coarse and sandy texture in ice cream.
Addition of carob extract decreased the colour and appearance scores of ice creams because of its colour from orange to brown. The highest mouth coating scores was the samples supplied with carob extract and whey powder. The improved mouthfeel of the samples containing carob extract and whey powder may be associated with decreased meltability.
Taste and odour score was greatest in sample E and least in sample B. It could be related to cheesy flavour of whey powder. When whey powder added with carob extract this flavour may be masked by carob extract. Control samples had the highest general acceptibility scores. It was followed by the sample supplemented with 1% carob extract and whey powder.
Addition of 1% carob extract and whey powder had improved on physical and sensory properties of ice cream. However, individual usage of whey powder had negatively
Sample* | Coldness | Firmness | Viscosity | Smoothness | Color and appearance | Mouth coating | Taste and odor | General acceptability |
---|---|---|---|---|---|---|---|---|
A | 5.28 ± 0.23b | 7.33 ± 0.325a | 6.35 ± 0.95a | 7.17 ± 0.055a | 9.36 ± 0.025b | 7.14 ± 0.135ab | 7.03 ± 0.085ab | 7.39 ± 0.055a |
B | 5.00 ± 0.12ab | 7.74 ± 0.0350a | 6.46 ± 0.045a | 7.44 ± 0.060a | 9.25 ± 0.085b | 7.22 ± 0.110ab | 6.86 ± 0.025a | 7.17 ± 0.030a |
C | 4.59 ± 0.04ab | 7.90 ± 0.065a | 6.77 ± 0.045ab | 7.61 ± 0.110a | 7.54 ± 0.160a | 7.44 ± 0.060b | 7.28 ± 0.055bc | 7.19 ± 0.165a |
D | 4.47 ± 0.03a | 8.04 ± 0.170a | 6.97 ± 0.030ab | 8.41 ± 0.140b | 7.69 ± 0.080a | 7.61 ± 0.165b | 7.28 ± 0.055bc | 7.77 ± 0.110a |
E | 4.79 ± 0.13ab | 7.47 ± 0.085a | 5.91 ± 0.250ab | 8.69 ± 0.140b | 7.24 ± 0.140a | 6.77 ± 0.000a | 7.39 ± 0.055c | 7.19 ± 0.140a |
F | 4.69 ± 0.08ab | 7.36 ± 0.025a | 5.90 ± 0.290b | 8.86 ± 0.025b | 9.44 ± 0.060b | 6.69 ± 0.080a | 7.92 ± 0.085d | 8.86 ± 0.140b |
*A: 0.5% whey powder. B: 1% whey powder. C: 0.5% whey powder +1% carob extract. D: 1% whey powder +1% carob extract. E: 1% carob extract. F: Control; **a,b,c Means in the same column followed by different letters were significantly different (p < 0.01).
affected smoothness, taste and odour and general acceptibility of probiotic ice creams.
Survival of probiotic bacteria was also studied in probiotic ice-cream with different carob extract and whey powder concentration during 90 days. Addition of carob extract and whey powder affected viable bacteria numbers significantly. The highest number was in the samples with 1% carob extract and whey powder. Increasing carob extract and whey powder concentration stimulated the growth of L. acidophilus and Bifidobacterium BB-12. The results suggested that the addition of carob extract and whey powder stimulated the growth of L. acidophilus and Bifidobacterium BB-12 and could be recommended for ice cream production.
Guler-Akin, M.B., Goncu, B. and Akin, M.S. (2016) Some Properties of Probiotic Yoghurt Ice Cream Supplemented with Carob Extract and Whey Powder. Advances in Microbiology, 6, 1010-1020. http://dx.doi.org/10.4236/aim.2016.614095