Mingruo Guo

ASSESSMENT OF POTENTIAL PROBIOTIC PROPERTIES OF LACTIC ACID BACTERIA AND YEAST STRAINS

ABSTRACT Four lactic acid bacteria (LAB) and three yeast strains isolated from a traditional Bulgarian cereal-based fermented beverage were assessed for potential probiotic properties. Acid and bile resistance, antipathogenic activity and antibiotic resistance of the strains were evaluated. Tolerance to low pH values (2.0–3.0) and high bile concentrations (0.2–2.0%) of the LAB and yeast strains varied, but all strains kept viable throughout the experiments. Antagonistic activity towards most of the eight test-pathogens was observed for one LAB (Lactobacillus plantarum B28) and two yeast strains (Candida rugosa Y28 and Candida lambica Y30). Antibiotic resistance (39 antibiotics) of the LAB strains was variable, but showed their potential for therapeutic application.

Isolation and preliminary probiotic selection of lactobacilli from koumiss in Inner Mongolia.

From 16 samples of traditional fermented koumiss collected in Inner Mongolia Autonomous Region of China, forty‐eight lactobacilli strains were isolated and phenotypically characterized by their abilities to ferment different carbohydrates and by additional biochemical tests. The dominant lactobacilli species were identified as L. casei (17 strains), L. helveticus (10 strains) and L. plantarum (8 strains), with a lower frequency of isolation for L. coryniformis subsp. coryniformis (5 strains), L. paracasei (3 strains), L. kefiranofaciens (2 strains), L. curvatus (1 strain), L. fermentum (1 strain) and W. kandleri (1 strain). The pH values of all these samples were ranging from 3.37 to 3.94. In isolates, L. casei Zhang, L. helveticus ZL12‐1, and L. plantarum BX6‐6 were selected as potentially probiotic strains through the preliminary tests including resistance to low acid, abilities to grow in MRS with bile salts, antimicrobial activities and the viabilities during prolonged cold storage in fermented milk. Moreover 16S rDNA was conducted to confirm the identification. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Relationship between the yield of cheese (Chevre) and chemical composition of goat milk

Abstract The relationships between goat milk constituents and cheese (Chevre, a fresh goat’s milk cheese) yield were determined to develop formula for predicting the moisture-adjusted yield of Chevre. Samples of commingled goat milk shipped to a commercial manufacturer of Chevre were collected weekly over a 12-month period and analyzed for milk fat, crude protein (CP), casein, total solids (TS), and mineral contents. The yield of Chevre made from the sampled milk was measured and adjusted to a 60% moisture content. There was a definite trend in the 60% moisture-adjusted yield of Chevre during the year, which ranged from 14% in June to 20% in December and January. Milk TS and CP contents were the most significant predictors of Chevre yield ( Y ): Y=2.64 TS −15.48 ( r 2 =0.81, P Y=8.6116 CP −12.7598 ( r 2 =0.79, P

Whey for mass production of Beauveria bassiana and Metarhizium anisopliae

Spore production of Beauveria bassiana and Metarhizium anisopliae was studied in a novel whey-based culture media. Spore yield and viability were determined for two B. bassiana (GHA-726 and CA-603) and two M. anisopliae (CA-1 and IMI 330189) isolates following production in three whey-based systems: solid, liquid, and a diphasic production system. Our study indicated that whey permeate can be used effectively for production of spores of entomopathogenic fungi. However, spore yield and viability were significantly influenced by fungal isolate, whey concentration, and the type of production process used. Under the conditions defined in the present study, spore yields ranging from 1.3x10(9)-10x10(11) spores l(-1) of whey medium could be obtained depending on the strain and production process used. Our study revealed that spores produced by all strains in whey-based solid and liquid media showed between 73-99% viability; germination rates were comparable with those obtained using the standard SDA medium. In the two-stage production process, the viabilities of conidia produced by GHA-726, CA-603, and CA-1 were 35-86, 32-98, and 6-29%, respectively; viability was correlated with whey concentration and isolates. Whey permeate can be used as a growth substrate for mass production of biocontrol fungi. We hypothesize that spore yield and viability could be improved by careful selection of whey content in the medium, incorporation of critical additives and optimization of culture conditions.

Heat-induced modifications of the functional properties of sodium caseinate

Abstract The effects of heating sodium casemate solutions (5–6%, w v , pH 7.0) at 120 or 132° C for 60 min on functionality were investigated by measuring solubility, viscosity, foaming and emulsifying properties. Solubility of the protein at pH 2.0–3.5 was increased markedly by the heat treatments, but there was little change at pH values above 5.5. The viscosity of Na casemate solution was decreased by the heat treatments. Heating reduced significantly the foaming and emulsifying capacity of Na casemate, but the foam stability appeared to be improved by the heating. The drainage of liquid from the foam appeared to follow first-order kinetics. The relative hydrophobicity also was reduced by the heat treatments.

Functional foods : principles and technology

Antioxidants and antioxidant rich foods Dietary fiber and dietary fiber rich foods Prebiotics and probiotics Lipids and lipid related functional foods Vitamins and minerals as functional ingredients Soy food products and their health benefits Sports drinks Human milk and infant formula.

Whey‐protein based environmentally friendly wood adhesives

Purpose – The purpose of this paper is to develop an environmentally safe aqueous polymer‐isocyanate (API) wood adhesive for structural uses with whey protein isolate (WPI) that is a by‐product of cheese making.Design/methodology/approach – The API formulations with whey proteins denatured at different heating temperatures and times, WPI/polyvinyl alcohol (PVA) denaturing processes, PVA contents and nano‐CaCO3 (as filler) contents were investigated and optimised according to the JIS K6806‐2003 standard.Findings – A whey‐protein based API adhesive was developed which had 28 h boiling‐dry‐boiling wet compression shear strength 6.81 MPa and dry compression shear strength 13.38 MPa beyond the required values (5.88 and 9.81 MPa, respectively) for structural use of commercial standards. The study also indicated that the thermal denaturation of 40 per cent WPI solution at 60‐63°C could unfold the globular structure of whey protein to some extent and therefore improve the bond strength and bond durability of whey...

Effects of Carbonation on Probiotic Survivability, Physicochemical, and Sensory Properties of Milk‐Based Symbiotic Beverages

Drinkable yogurt is a popular beverage in the United States and there may be a niche for carbonated drinkable yogurt in the functional foods market. Pomegranate (P) and vanilla (V) yogurt beverages were formulated, containing inulin as a prebiotic, along with probiotic bacteria Lactobacillus acidophilus and Bifidobacterium, to produce symbiotic products. These beverages were stabilized with high-methoxyl pectin and whey protein concentrate and compared to samples with approximately 2 volumes of added carbon dioxide (CO2 ). Samples were stored in sealed glass bottles at 4 °C for 9 wk for evaluation of physicochemical and functional properties. Trials were carried out in triplicate and 3 replicates from each trial were analyzed. Physicochemical attributes were analyzed using standard AOAC methods. Survivability of the probiotics and changes in pH and viscosity were measured weekly. Chemical composition of the carbonated beverages was: protein: 1.58 ± 0.05%, 1.59 ± 0.06%, fat: 1.24 ± 0.2%, 1.18 ± 0.11%, total solids: 14.78 ± 0.11%, 14.93 ± 0.05%, ash: 0.49 ± 0.02%, 0.46 ± 0.03%, and carbohydrate (by difference): 11.47 ± 0.12%, 11.69 ± 0.14% for P and V, respectively. Both L. acidophilus and Bifidobacterium were stable and remained above 10(6) CFU/g for both flavors of beverage both with and without carbonation. The new manufacturing technology for these prototypes may have potential for commercialization of carbonated symbiotic milk-based beverages.

Nitrogen and mineral distribution in infant formulae

Abstract Nitrogen and mineral distributions in infant formulae were compared to raw and pasteurized milk samples. The percentage of total nitrogen present in the fat fraction after centrifugation ranged from 20 to 50% among the infant formulae, whereas only 1.4% was found in the fat fraction of raw milk. Recovery of individual minerals from the three fractions exceeded 95% in all cases except for Zn, which exceeded 91%. Ca in the fat fraction of infant formulae ranged from 18 to 30%, whereas only 1.4–1.7% of the total Ca was recovered in the fat fraction of the raw milk and the pasteurized milk samples. P, Zn, Mg and Fe followed patterns similar to Ca. In contrast, 80–90% of the K and Na were found in the serum fraction of the infant formulae and milk samples. Electrophoretograms of the formulae showed that the proteins in the fat fraction were mainly caseins and β-lactoglobulin. The major proteins in the serum were β-lactoglobulin and α-lactalbumin with small casein bands. All the main proteins were found in the pellet. Electron micrographs of the formulae showed extensive attachment of denatured whey proteins and casein micelles to fat globule surfaces. Whey protein-casein micelle complexes were formed due to protein-protein interactions induced during processing. Electron-dense granules were also present on the lipid droplet surfaces and dispersed in the denatured whey proteins clusters and casein micelles of the infant formulae samples. Energy dispersive spectroscopy X-ray microanalysis of these electron-dense granules revealed the presence of K, P, Fe and Zn. These granules were not present in milk samples.

Formulation designs and characterisations of whey‐protein based API adhesives

Purpose – The purpose of this paper is to investigate the effects of the components of whey‐protein based aqueous polymer‐isocyanate (API) adhesives on the bond strength.Design/methodology/approach – The bond test (according to the JIS K6806‐2003 standard), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterise the whey‐protein based API adhesives with various formulations and processing technologies.Findings – The good bond strength of the optimised whey‐protein based API adhesive was attributed to the formation of strong chemical bonds in the bondline and to the additions of polyisocyanate, polyvinyl alcohol (PVA) and nano‐CaCO3 powder that improved adhesive cohesive strength by either chemical crosslinks or mechanical interlocking. The blending procedures of whey protein, PVA, polyvinyl acetate (PVAc) and p‐p‐MDI had great impacts on the performances of the whey‐protein based API adhesives.Research limitations/implications – SEM micrographs showe...