The effects of enzymatic interesterification on the physical-chemical properties of blends of lard and soybean oil

The main goal of the present research effort was to evaluate the physical-chemical properties of blends of lard and soybean oil following enzymatic interesterification catalyzed by an immobilized lipase from Thermomyces lanuginosa (Lipozyme (TM) TL IM). Lipase-catalyzed interesterification produced new tri-acylglycerols that changed the physical-chemical properties of the fat blends under study. Solid fat content (31.3 vs 31.5 g/100 g), consistency (104.7 vs 167.6 kPa), crystallized area (0.6 vs 11.8) and softening point (31.8 vs 32.2 degrees C) of lard increased after interesterification, and this was mostly due to the increase of SSS (saturated) + SSU (disaturated-monounsaturated) triacylglycerols. These contents (SSU + SSS) increased in lard after interesterification from 42.9 to 46.7 g/100 g. The interesterified blends exhibited lower values for the physical properties when compared with their counterparts before enzymatic interesterification. The interesterification of blends of lard with soybean oil increased the amounts of UUU (triunsaturated) and SSS triacylglycerols and reduced the amounts of UUS (diunsaturated-monosaturated) triacylglycerols. The interesterified blends of lard and soybean oil demonstrated physical properties and chemical composition similar to human milk fat and they could be used for the production of a human milk fat substitute. (C) 2009 Elsevier Ltd. All rights reserved.

Growth and acidification performance of probiotics in pure culture and co-culture with Streptococcus thermophilus: The effect of inulin

Inulin was used as a prebiotic to improve the quality and consistency of skim milk fermented by co-cultures and pure Cultures of Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus bulgaricus and Bifidobacterium lactis with Streptococcus thermophilus. We compared, either in the presence or absence of 4 g inulin/100 g, the results of the main kinetic parameters, specifically the generation time (t(g)), the maximum acidification rate (V(max)). and the times to reach V(max) (t(max)), to attain pH 5.0 (t(pH5.0)) and to complete the fermentation (t(pH4.5)). Post-acidification, lactic acid formation and cell counts were also determined and compared, either 1 day after the fermentation was complete or after 7 day storage at 4 degrees C. In general, inulin addition to the milk increased in co-cultures V(max), decreased t(max), t(g) and t(pH4.5), favored post-acidification, exerted a bifidogenic effect, and preserved almost intact cell viability during storage. In addition, S. thermophilus was shown to stimulate the metabolism of the other lactic bacteria. Contrary to co-cultures, most of the effects in pure Cultures were not statistically significant. The most important aspect of this paper is the use of the generation time as a toot to investigate the microbial response to inulin addition. (c) 2009 Elsevier Ltd. All rights reserved.

Viability of Lactobacillus acidophilus La-5 added solely or in co-culture with a yoghurt starter culture and implications on physico-chemical and related properties of Minas fresh cheese during storage

The effect of a probiotic culture of Lactobacillus acidophilus (La-5), added solely or in co-culture with a starter culture of Streptococcus thermophilus, on texture, proteolysis and related properties of Minas fresh cheese during storage at 5 degrees C was investigated. Three cheese-making trials were prepared and produced with no addition of cultures (T1 - control), supplemented with La-5 (T2), and with La-5 + S. thermophilus (T3). Viable counts of La-5 remained above 6.00 log cfu g(-1) during the whole storage for T2, reaching 7.00 log cfu g(-1) on the 14th day. For T3, the counts of La-5 remained above 6.00 log cfu g(-1) after 7 days of storage. Due to the presence of S. thermophilus, T3 presented the highest proteolytic index increase and titratable acidity values. Nevertheless, these results and S. thermophilus addition had no influence on viability of La-5 which presented satisfactory populations for a probiotic food. Moreover, the use of a yoghurt culture for the production of Minas fresh cheese T3 supplemented with La-5 resulted in a good quality product, with a small rate of post-acidification, indicating that traditional yoghurt culture could be employed in co-culture with La-5 to improve the quality of this cheese. (C) 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.

Acidification rates of probiotic bacteria in Minas frescal cheese whey

The acidification rates of Lactobacillus delbrueckii subsp. bulgarieus (Lb), Lactobacillus acidophilus (La), Lactobacillus rhamnosus (Lr), and Bifidobacterium animalis subsp. lactis (Bl) in co-culture with Streptococcus thermophilus (St) were studied in Minas frescal cheese whey. Effects of the co-culture composition and the final pH values on the kinetic parameters of acidification, post-acidification and counts of health promoting micro-organisms were also studied. Fermentation time to reach pH 4.5 was longer when St-Lr co-culture was used, while St-Lb had the shortest fermentation time when compared with the other co-culture combinations. All products showed development of acidity during the storage period and lowest values had been observed employing St-Bl co-culture. The technological interest of using M. frescal cheese whey for the production of a probiotic lactic beverage is discussed in this article. (C) 2007 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.

Evaluation of culture media for enumeration of Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium animalis in the presence of Lactobacillus delbrueckii subsp bulgaricus and Streptococcus thermophilus

The study compared the growth capability of probiotic (Lactobacillus acidophilus La05, Lactobacillus casei Lc01 and Bifidobacterium animalis Bb12) and non-probiotic (Lactobacillus delbrueckii subsp bulgaricus and Streptococcus thermophilus) cultures on twenty-one culture media grouped according to selectivity: nonselective agars, selective agars without antibiotics and MRS agars containing different combinations of lithium chloride, cystein, bile salts and antibiotics. Four of these media were selected for quantitative enumeration of L acidophilus La05, L casei Lc01, and B. animalis Bb12. The best culture media and incubation conditions for enumeration of the probiotic cultures were: B. animalis: MRS agar with dicloxacillin, 37 degrees C or 42 degrees C, anaerobiosis; L acidophilus: MRS agar with bile salts, 37 degrees C or 42 degrees C, aerobiosis; L casei: MRS agar with lithium chloride and sodium propionate, 37 degrees C or 42 degrees C, aerobiosis or anaerobiosis. Plating on MRS with glucose replaced by maltose, 37 degrees C or 42 degrees C, anaerobiosis, will distinguish probiotic from non-probiotic cultures. For enumeration of each probiotic in a mixed culture, the following media and incubation conditions were recommended: B. animalis: 4ABC-MRS, 42 degrees C, anaerobiosis, L acidophilus: LC medium, 42 degrees C, aerobiosis or anaerobiosis and L casei: LP-MRS, 42 degrees C, aerobiosis or anaerobiosis. In all experiments, differences in counts using pour plating or surface plating were not significant (P <= 0.05). (C) 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.

Inulin and oligofructose improve sensory quality and increase the probiotic viable count in potentially synbiotic petit-suisse cheese

The influence of inulin, oligofructose and oligosaccharides from honey, combined in different proportions, on the consumers` sensory acceptance, probiotic viable count and fructan content of novel potentially synbiotic petit-suisse cheeses was investigated. Probiotic populations varied from 7.20 up to 7.69 log cfu g(-1) (Bifidobacterium animalis subsp. lactis) and from 6.08 up to 6.99 log cfu g(-1) (Lactobacillus acidophilus). The highest fructan contents were achieved by the cheese trials containing oligofructose and/or inulin (above 8.90 g 100 g(-1)). The control trial showed the lowest mean acceptance (6.63) after 28 days of refrigerated storage, whereas the highest acceptance (7.43) was observed for the trial containing 10 g 100 g(-1) oligofructose. Acceptance increased significantly during storage (P < 0.05) only for cheeses supplemented with oligoftuctose and/or inulin. Cheeses containing honey did not perform well enough compared to the cheeses with addition of inulin and/or oligofructose, and the best synbiotic petit-suisse cheese considering sensory and technological functional features was that containing oligofructose and inulin combined, therefore encouraging the commercial product use. (c) 2007 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.