We investigated the effects of lactoferrin on the growth of L. acidophilus CH-2, Bifidobacterium breve ATCC 15700, B. longum ATCC 15707, B. infantis ATCC 15697, and B. bifidum ATCC 15696. The growth of L. acidophilus was stimulated by bovine holo-lactoferrin but not by apo-lactoferrin. With bifidobacteria, bovine lactoferrin stimulated growth of three strains: B. breve, B. infantis and B. bifidum under certain conditions. Both apoprotein and holoprotein had similar effects. However, B. longum growth was not affected by lactoferrin. Thus, the mechanism of stimulating growth of bifidobacteria may be different from that of L. acidophilus. By far-western blotting using biotinylated lactoferrin and horseradish peroxidase-conjugated streptavidin, lactoferrin-binding proteins were detected in the membrane protein fraction of L. acidophilus, B. bifidum, B. infantis and B. breve. The molecular weights of lactoferrin-binding proteins of L. acidophilus were estimated from SDS-polyacrylamide gel electrophoresis to be 27, 41 and 67 kDa, and those of the three bifidobacterial strains were estimated to be 67-69 kDa. However, no such lactoferrin-binding components were detected in the membrane fraction of B. longum. It is interesting that the appearance of lactoferrin-binding proteins in the membrane fraction of these species corresponds to their growth stimulation by lactoferrin.

Optimum conditions of solid phase microextraction (SPME) analysis of the headspace volatile compounds of Parmesan cheese in airtightly sealed 100-mL bottles were developed. The coefficient of variation of SPME analysis on the headspace volatile compounds of Parmesan cheese was 2%. The reproducibility of SPME was improved by a combination of sampling at -10 degrees C, controlling the sample temperature, and uniform magnetic stirring of samples during equilibrium and isolation steps. The sensitivity of SPME increased by 125% in total peak areas by a combination of 40 min of sonication and 25% (w/v) sodium phosphate solution, compared with that of samples containing deionized water only (P < 0.05). The addition of salt solution or sonication treatment in samples increased the headspace volatile compounds of cheese quantitatively without producing any new volatile compounds.

Light-induced volatile compounds in goat cheese were studied by a combination of solid phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS), headspace oxygen depletion, and sensory evaluation. Samples stored under fluorescent light for 2 days at 30 degrees C had 90% more volatile compounds and 4 times more headspace oxygen depletion than samples stored in the dark at 30 degrees C. The volatiles 1-heptanol, heptanal, nonanal, and 2-decenal were formed and increased only in the light-stored samples, which may be formed from singlet oxygen oxidation of unsaturated fatty acids. Sensory evaluation showed that samples stored under light had significantly more off-flavor than samples stored in the dark at 30 degrees C (P < 0.05), and 1-heptanol, heptanal, nonanal, and 2-decenal increased the goat cheese off-flavor significantly (P < 0.05).

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This study was performed to evaluate the antioxidant activity of yogurt fermented at low temperature and the anti-inflammatory effect it has on induced colitis with 2.5% dextran sodium sulfate (DSS) in Balb/c mice. Yogurt premix were fermented with a commercial starter culture containing Lactobacillus acidophilus, Bifidobacterium lactis, Streptococcus thermophilus, and Lactobacillus delbrueckii subsp. bulgaricus at different temperatures: 22°C (low fermentation temperature) for 27 h and 37°C (general fermentation temperature) for 12 h. To measure antioxidant activity of yogurt samples, DPPH, ABTS+ and ferric reducing antioxidant potential (FRAP) assays were conducted. For animal experiments, inflammation was induced with 2.5% DSS in Balb/c mice. Yogurt fermented at low temperature showed higher antioxidant activity than that of the yogurt fermented at general temperature. In the inflammatory study, IL-6 (interleukin 6) was decreased and IL-4 and IL-10 increased significantly in DSS group with yogurt fermented at general temperature (DYG) and that with yogurt fermented at low temperature (DYL) compared to that in DSS-induced colitic mice (DC), especially DYL had higher concentration of cytokines IL-4, and IL-10 than DYG. MPO (myeloperoxidase) tended to decrease more in treatments with yogurt than DC. Additionally, yogurt fermented at low temperature had anti-inflammatory activity, although there was no significant difference with general temperature-fermented yogurt (p>0.05).