ABSTRACT
This study was conducted to investigate the probiotic properties of twenty lactic acid bacteria (LAB) previously isolated and identified from naturally fermented kunun-zaki (a Nigerian fermented cereal beverage). The probiotic properties of the twenty lactic acid bacteria (LAB) isolates were assessed using different standard methods and agar well diffusion method. The results showed that most of the isolates tolerated acidic pH and survived at 30-40oC. All the tested LAB isolates grew at 1% NaCl concentration and remarkably, six LAB isolates {L. brevis (3) and L. plantarum (3)} exhibited good growth at higher NaCl concentrations (10-15%). The highest percentage of cellular auto-aggregation was observed in L plantarum (84.86%) and the lowest was obtained in L. brevis (27.44%). All the twenty LAB isolates tested in-vitro in this study grew in bile salt; fermented glucose; produced good aroma; produced no hemolysis revealing they were not pathogenic and produced antagonistic activity against selected pathogens (Staphylococcus aureus, Salmonella typhi, Shigella. dysenteriae and Escherichia coli) which made them suitable and safe for human consumption as potential probiotics and for industrial purposes.
ABSTRACT
Aim: To study the commercial preparation of Kunun zaki in three locations in Port Harcourt namely; Bori-camp, Rumuodomaya and Mgbuogba, to compare the microbiological, physico-chemical, and nutritional qualities of commercial and laboratoryprepared Kunun drinks and to establish the critical control points at various points of the production process. Place and Duration of Study: Sample collection areas were Bori-camp, Rumuodomaya, Mgbuogba, and the Laboratory, between August and December 2012. Sample analysis was done in the Food and Industrial Microbiology Laboratory of University of Port Harcourt. Methodology: At selected stages of preparation of Kunun zaki from Bori-camp, Rumuodomaya, Mgbuogba and the Laboratory, nine samples each were collected into sterile screw-capped 50cl bottles for analysis at the Food and Industrial Microbiology laboratory of University of Port Harcourt. Analyses carried out were to determine the microbial contaminants, proximate and physico-chemical parameters. Samples of fresh Kunun zaki were stored at 5ºC for three days for analysis on effect of storage. Results: The microorganisms associated with freshly prepared Kunun zaki and that stored at refrigeration temperature (5ºC) for three days were Lactobacillus spp., Bacillus spp., Leuconostoc spp., Streptococcus spp., Micrococcus spp., Staphylococcus spp., Pseudomonas spp., Escherichia coli, Enterobacter spp., Penicillium spp., Mucor spp., Aspergillus spp., Rhizopus spp., Candida spp., and Saccharomyces spp. Freshlyprepared Kunun zaki had the highest coliform and staphylococci counts of 8.0x104 and 8.3x103cfu/ml respectively in Bori-camp preparation, while Laboratory-prepared Kunun zaki harboured none of these organisms. Total viable counts of commercially-prepared (Bori-camp, Rumuodomaya, and Mgbuogba) products ranged from 2.50x104 to 1.53x106cfu/ml, while Laboratory-prepared product was 6.0x104cfu/ml. Fungal counts of commercially-prepared Kunun zaki ranged from 2.5x103 to 1.36x105cfu/ml, while Laboratory-prepared Kunun zaki had fungal counts of 5.6x102cfu/ml. Yeasts were the main spoilage organisms which persisted at storage temperature of 5ºC for three days. The protein and carbohydrate contents, as well as calcium, zinc, copper, and manganese decreased after being stored for three days at 5ºC. Conclusion: Therefore Kunun zaki could be safely consumed after storage at 5ºC for three days, if good manufacturing practices like the use of fresh non-moldy grains and spices, cooled boiled water for grain washing and steeping, sterile stainless steel containers, steam-sterilized grinder, and sterile screw-capped bottles for packaging be applied at all the production stages. Educating the producers on the hazards, critical control points (steeping, milling and packaging), and temperature maintenance for Kunun zaki preparation are important.
Subject(s)
Beverages/analysis , Edible Grain/chemistry , Hazard Analysis and Critical Control Points , Food Handling , Food Technology , Nigeria , Panicum/chemistry , /physiologyABSTRACT
Kunun-zaki was produced using ginger and garlic and stored under ambient conditions for 10 days. The microbiological load and the shelf life of the drink were investigated. Diverse microbial genera: Lactobacillus, Bacillus, Staphylococcus, Aspergillus, Penicillum, Fusarium and Saccharomyces were isolated from samples. The effect of ginger and garlic separately were compared to the combined effect of ginger and garlic in reducing the microbial population. Of all the treatments, garlic (2g in 200mls or 0.01%w/v) was most effective in reducing the microbial populations. In contrast, treatment with 1g of ginger was least effective in reducing the microbial populations. Shelf life based on sensory overall acceptability and microbial quality of the samples varied with treatments but combination treatment with 2g in 200mls(0.01%w/v) ginger and garlic extended the shelf life by approximately four (4) days whereas other treated samples showed marginal enhanced shelf life of 2days. However, untreated control sample exhibited remarkably high microbial load and was virtually unacceptable after 24h of production. The result shows the potential of the combination treatment of ginger and garlic as antimicrobials and in extending the shelf life of Kunun-zaki.
ABSTRACT
This study was aimed to investigate the effects of chemical treatment as well as pasteurization on the shelf life of “kunun zaki” (a non-alcoholic beverage commonly consumed by the people of northern Nigeria), to increase the shelf life and preserve the quality of the beverage. Kunun zaki was produced by dry -cleaning, washing, steeping (sorghum for 24 hours and maize for 48 hours), malting for 72 hours at room temperature, wet milling, mixing, cooking and filtering to obtain the liquor. The product was treated with 0.1% sodiumbenzoate or sodium metabisulphite or their combinations. These were packed and pasteurized in bottles at 60oC for one hour. Another batch of samples were chemically treated but not pasteurized. Pasteurized samples which were not chemically treated served as control. Samples were stored at ambient temperature and monitored for changes in pH, titratable acidity, total solid, total sugars, acceptability and colour for four weeks. The pH and sugar decreased and the decrease was more pronounced in non pasteurized samples irrespective of chemical treatment. Titratable acidity increased in all samples with storage time. Pasteurized kunun zaki which received no chemical treatment deteriorated after one week of storage. Samples treated with 0.1% sodium benzoate or sodium metabisulphite or their combination without pasteurization deteriorated after two weeks of storage. Samples which were similarly treated and pasteurized were stable for more than three weeks. Pasteurization enhanced effectiveness of chemical preservation and acceptability of kunun zaki.
ABSTRACT
This study was aimed to investigate the effects of chemical treatment as well as pasteurization on the shelf life of “kunun zaki” (a non-alcoholic beverage commonly consumed by the people of northern Nigeria), to increase the shelf life and preserve the quality of the beverage. Kunun zaki was produced by dry -cleaning, washing, steeping (sorghum for 24 hours and maize for 48 hours), malting for 72 hours at room temperature, wet milling, mixing, cooking and filtering to obtain the liquor. The product was treated with 0.1% sodiumbenzoate or sodium metabisulphite or their combinations. These were packed and pasteurized in bottles at 60oC for one hour. Another batch of samples were chemically treated but not pasteurized. Pasteurized samples which were not chemically treated served as control. Samples were stored at ambient temperature and monitored for changes in pH, titratable acidity, total solid, total sugars, acceptability and colour for four weeks. The pH and sugar decreased and the decrease was more pronounced in non pasteurized samples irrespective of chemical treatment. Titratable acidity increased in all samples with storage time. Pasteurized kunun zaki which received no chemical treatment deteriorated after one week of storage. Samples treated with 0.1% sodium benzoate or sodium metabisulphite or their combination without pasteurization deteriorated after two weeks of storage. Samples which were similarly treated and pasteurized were stable for more than three weeks. Pasteurization enhanced effectiveness of chemical preservation and acceptability of kunun zaki.
ABSTRACT
Millet grains were steeped in 1% sodium metabisulphite (1:2w/v) for 5min and subsequently washed and wet milled; the cereal paste was gelatinized with boiling water (1:1w/v, 76±2oC) and immediately hydrolyzed separately either with α+β-amylases, α+amyloglucosidase or rice malt. The hydrolyzed cereal starch was inoculated with a 12h starter culture (2%v/w) of Lactobacillus plantarum, L. fermentum, and Lactococcus lactis and fermented for 6h. Chemical (pH, titratable acidity), physical (viscosity, S.G., total soluble solids) and sensory quality of the hydrolyzed cereal slurry and the fermented product were determined. The results obtained in this study show that the pH of the products decreased with concomitant increases in titratable acidity (% lactic acid) during production; however, the decrease in pH was more prominent in the ‘kunun-zaki’ produced from the cereal starch treated with α+β-amylases and this, differed from the other products (p<0.05). There was an increase in viscosity with a corresponding decrease in the total soluble solids (TSS) in all the samples throughout production; the decrease in TSS is an indication of an increase in the activity of the fermenting LABs. Furthermore, the sensory quality attributes of the three products were generally acceptable by the taste panelist in all the parameters evaluated (appearance, aroma, taste), however, the ‘kunun-zaki’ produced using the cereal starch treated with rice malt was preferred in taste and this was significantly different (p<0.05) from the other products. This study has shown that ‘kunun-zaki’ of acceptable quality could be produced within 7h, the marked reduction in the processing time of ‘kunun-zaki’ from 12-7h could encourage large-scale production of this popular drink.