Browsing by Author "Mutukumira AN"

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    Bioactive Yoghurt Containing Curcumin and Chlorogenic Acid Reduces Inflammation in Postmenopausal Women
    (MDPI (Basel, Switzerland), 2022-11-02) Ahmed Nasef N; Thota RN; Mutukumira AN; Rutherfurd-Markwick K; Dickens M; Gopal P; Singh H; Garg ML; Bordoni A
    Menopause is marked by a gradual and permanent decrease of estrogen from the ovaries, leading to metabolic and physiological changes in the body. Combined with increased body mass index, postmenopausal women have elevated systemic inflammation and metabolic disturbances leading to increased risk of developing chronic diseases. A bioactive coconut yoghurt containing curcumin and chlorogenic acid was developed with the potential to target inflammatory processes. In this randomized crossover study, healthy postmenopausal women with a BMI of 25-40 were recruited to consume 125 g of either the bioactive or placebo yoghurt. Blood samples were collected at baseline, 30 min, and 1, 2, 3 and 4 h postprandially. Plasma inflammatory markers (TNFα and IL6) and metabolic markers (triglycerides, insulin and glucose) were measured. Participants had significantly lower plasma TNFα Cmax after consumption of the bioactive yoghurt compared to placebo (mean difference = 0.3 pg/mL; p = 0.04). Additionally, plasma TNFα was significantly lower postprandially compared to baseline after consumption of the bioactive yogurt but not the placebo. No differences were observed in the metabolic markers measured. Conclusions: The bioactive yoghurt fortified with curcumin and chlorogenic acid has the potential to reduce inflammatory mediators; however, a larger and longer-term study is required to confirm these findings.
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    Carbohydrate composition, viscosity, solubility, and sensory acceptance of sweetpotato- and maise-based complementary foods
    (Food and Nutrition Research, 2013) Amagloh FK; Mutukumira AN; Brough L; Weber JL; Hardacre A; Coad J
    Background: Cereal-based complementary foods from non-malted ingredients form a relatively high viscous porridge. Therefore, excessive dilution, usually with water, is required to reduce the viscosity to be appropriate for infant feeding. The dilution invariably leads to energy and nutrient thinning, that is, the reduction of energy and nutrient densities. Carbohydrate is the major constituent of food that significantly influences viscosity when heated in water. Objectives: To compare the sweetpotato-based complementary foods (extrusion-cooked ComFa, roller-dried ComFa, and oven-toasted ComFa) and enriched Weanimix (maize-based formulation) regarding their 1) carbohydrate composition, 2) viscosity and water solubility index (WSI), and 3) sensory acceptance evaluated by sub-Sahara African women as model caregivers. Methods: The level of simple sugars/carbohydrates was analysed by spectrophotometry, total dietary fibre by enzymatic-gravimetric method, and total carbohydrate and starch levels estimated by calculation. A Rapid ViscoTM Analyser was used to measure viscosity. WSI was determined gravimetrically. A consumer sensory evaluation was used to evaluate the product acceptance of the roller-dried ComFa, oven-toasted ComFa, and enriched Weanimix. Results: The sweetpotato-based complementary foods were, on average, significantly higher in maltose, sucrose, free glucose and fructose, and total dietary fibre, but they were markedly lower in starch content compared with the levels in the enriched Weanimix. Consequently, the sweetpotato-based complementary foods had relatively low apparent viscosity, and high WSI, than that of enriched Weanimix. The scores of sensory liking given by the caregivers were highest for the roller-dried ComFa, followed by the oven-toasted ComFa, and, finally, the enriched Weanimix. Conclusion: The sweetpotato-based formulations have significant advantages as complementary food due to the high level of endogenous sugars and low starch content that reduce the viscosity, increase the solubility, impart desirable sensory characteristics, and potentially avoid excessive energy and nutrient thinning.
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    Identification of dominant lactic acid bacteria and yeast in rice sourdough produced in New Zealand
    (Elsevier BV, 2021-10-21) Yang Q; Rutherfurd-Markwick K; Mutukumira AN
    This study characterised a commercial New Zealand gluten free (GF) rice sourdough and its starter culture composition. Acidity of the mother sourdough, dough before proofing and dough after proofing was determined during the production of rice sourdough bread, and colour was measured for the baked bread. Yeast and lactic acid bacteria (LAB) were enumerated in the rice sourdough samples and representative colonies characterised using API kits and sequenced by the Internal Transcribed Spacer and 16 S rRNA region. Sourdough LAB isolates were identified as Lactobacillus (L.) papraplantarum DSM 10667 and L. fermentarum CIP 102980 and the yeast isolates as Saccharomyces (S.) cerevisiae CBS 1171. Dough acidity increased significantly (p < 0.05) during fermentation due to the metabolic activities of the sourdough cultures. After baking, the colour of the rice sourdough bread crust was similar to that of unleavened wheat bread (golden brown). The improved colour of the rice sourdough bread crust may be a result of combined use of sourdough technique and optimal baking conditions. The results of this study may allow bakers to improve the overall quality of GF rice sourdough baked bread by selecting suitable fermentation and baking parameters.
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    Influence of Operating Conditions on Reuterin Production Using Resting Cells of Limosilactobacillus reuteri DPC16
    (MDPI (Basel, Switzerland), 2022-05-16) Sun Y; Gutierrez-Maddox N; Mutukumira AN; Maddox IS; Shu Q; Raganati F; Procentese A
    Limosilactobacillus reuteri strains can secrete a potentially valuable chemical and broadspectrum antimicrobial substance named reuterin (3-hydroxypropionaldehyde, 3-HPA). L. reuteri DPC16 is a novel and patented probiotic strain that is used commercially because of its proven ability to kill various foodborne pathogens. A two-step process has been developed for reuterin production from glycerol using L. reuteri DPC16. Cells were grown, followed by harvesting, and then were incubated with glycerol for reuterin production. Parameters investigated during the glycerol conversion included the initial glycerol concentration, the biomass concentration, pH, culture age at harvesting, conversion time, and temperature. The highest reuterin yield was obtained using 21 g/L 24 h old cells, to convert glycerol solution (300 mmol/L) in 1 h at 30◦ C and pH 6.2. The most efficient transformation of glycerol to reuterin was achieved in approximately 20 h of growth of cells at 25◦ C and pH 6.8. Using the regression equation of this study, the maximum concentration of reuterin can be obtained using 25 g/L 20 h old DPC6 cells to ferment 350 mmol/L glycerol (initial concentration) for 2 h at 25◦ C and pH 6.8 The ranking of effects on reuterin production for the six single factors was glycerol concentration > pH > conversion time > biomass concentration > temperature > culture age.
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    Kombucha: Production and Microbiological Research
    (MDPI (Basel, Switzerland), 2022-10-31) Wang B; Rutherfurd-Markwick K; Zhang X-X; Mutukumira AN
    Kombucha is a sparkling sugared tea commonly prepared using a sugared tea infusion and fermented at ambient temperature for several days using a cellulose pellicle also called tea fungus that is comprised of acetic acid bacteria and yeast. Consumption of Kombucha has been reported as early as 220 B.C. with various reported potential health benefits and appealing sensory properties. During Kombucha fermentation, sucrose is hydrolysed by yeast cells into fructose and glucose, which are then metabolised to ethanol. The ethanol is then oxidised by acetic acid bacteria (AAB) to produce acetic acid which is responsible for the reduction of the pH and also contributes to the sour taste of Kombucha. Characterisation of the AAB and yeast in the Kombucha starter culture can provide a better understanding of the fermentation process. This knowledge can potentially aid in the production of higher quality products as these microorganisms affect the production of metabolites such as organic acids which are associated with potential health benefits, as well as sensory properties. This review presents recent advances in the isolation, enumeration, biochemical characteristics, conventional phenotypic identification system, and modern genetic identification techniques of AAB and yeast present in Kombucha to gain a better understanding of the microbial diversity of the beverage.
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    Microencapsulation of Limosilactobacillus reuteri DPC16 by spray drying using different encapsulation wall materials
    (Wiley Periodicals LLC, 2022-10-27) Wang F; Mutukumira AN
    Most probiotics are delivered in liquid media which tends to limit their shelf life thus, they are not convenient for the modern lifestyles. In this study, Limosilactobacillus reuteri DPC16 was encapsulated in 10% reconstituted skim milk (RSM), 10% gum Arabic, 10% maltodextrin, and a mixed wall material (2.5% whey protein isolate/2.5% gum Arabic/2.5% inulin/2.5% sucrose), (w/w). The mixture was then spray-dried at 160°C/80°C and/or 180°C/100°C inlet/outlet temperatures. The spray-dried DPC16 microcapsules were characterized for viable cells of the probiotic, aw, and morphology. Results showed that at the inlet/outlet temperatures of 160°C/80°C, RSM as an encapsulation wall material had the highest cell counts (98.06% ± 0.86%) with 0.196 ± 0.010 aw. Most of the powder particles (RSM) were spherical with dented surfaces. At 180°C/100°C, about 84% DPC16 cells survived in RSM capsules. Thus, RSM showed good potential as an encapsulating wall material to maintain high DPC16 cell viability during spray drying. Novelty impact statement: The encapsulation of Limosilactobacillus reuteri DPC16 using reconstituted skim milk (RSM) by spray drying at elevated inlet/outlet temperatures had lower encapsulation efficiency (EE), water activity, and smaller particle size of the microcapsules compared to RSM microcapsules spray-dried at low temperatures. Mixed wall material comprising gum Arabic, whey protein isolate, inulin, and sucrose produced microcapsules with relatively high EE, low water activity, and some microcapsules with smoother surfaces which could improve powder solubility.
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    Phenotypic and genotypic characterisation of Lactobacillus and yeast isolates from a traditional New Zealand Māori potato starter culture
    (Elsevier BV, 2022-08-26) Sun J; Silander O; Rutherfurd-Markwick K; Wen D; Davy TP-P; Mutukumira AN
    Parāroa Rēwena is a traditional Māori sourdough produced by fermentation using a potato starter culture. The microbial composition of the starter culture is not well characterised, despite the long history of this product. The morphological, physiological, biochemical and genetic tests were conducted to characterise 26 lactic acid bacteria (LAB) and 15 yeast isolates from a Parāroa Rēwena potato starter culture. The results of sugar fermentation tests, API 50 CHL tests, and API ID 32 C tests suggest the presence of four different LAB phenotypes and five different yeast phenotypes. 16S rRNA and 26S rRNA sequencing identified the LAB as Lacticaseibacillus paracasei and the yeast isolates as Saccharomyces cerevisiae, respectively. Multilocus sequence typing (MLST) of the L. paracasei isolates indicated that they had identical genotypes at the MLST loci, to L. paracasei subsp. paracasei IBB 3423 or L. paracasei subsp. paracasei F19. This study provides new insights into the microbial composition of the traditional sourdough Parāroa Rēwena starter culture.