Asian Food Science Journal

Aim: The present work was aimed at ensuring the accurate taxonomic identification of the fermentation organisms previously isolated from spontaneously fermented cassava for the purpose of safety assessment and quality assurance.

Study Design: Purposive sampling method was used as all the five isolated organisms (from the previous study); 2 bacterial and 3 fungal organisms were characterized using molecular methods.

Place and Duration of Study:  The genotypically characterized organisms are from a previous study carried out in May 2016 where lactic acid bacterial and fungal organisms were isolated from spontaneously fermented cassava. 

Methodology: Genomic DNA was extracted from the lactic acid microorganisms and this was used as a template in a polymerase chain reaction (PCR) reaction. The 16s rRNA genes were amplified for the bacterial isolates while nuclear ribosomal internal transcribed spacer (ITS) genes were targeted for the fungal isolates. The amplicons were electrophoresed on 2% agarose gel prepared with Tris Borate Ethylenediamintetraacetate (TBE) buffers stained with ethidium bromide. The sizes of the corresponding amplicon captured on gel images were compared with that of the ladder to determine their sizes. Furthermore, sequences of the PCR products were analyzed and the chromatograms subjected to BLAST (Basic Local Alignment Search Tool) analyses to identify the lactic acid organisms.

Results: The 3 fungal isolates were identified as Schizophyllum commune (MK 431022), Aspergillus oryzae (MK434151), Aspergillus sydowii (MK434152), while the bacterial isolates were identified as Bacillus spp (MK450345) and Bacillus spp (MK 449018). A high level of discrepancies was observed when the results of identification of the same isolates by biochemical methods in an earlier report were compared with the results from the present study using molecular methods. 

Conclusion: The identification and characterization of the isolates and the discrepancies between the outcomes of the biochemical and molecular methods underscore the limitations of phenotypic (biochemical) methods in characterizing organisms that may eventually be used as starter organisms in food fermentation. The present result makes quality assurance and safety assessment of foods prepared using these organisms as starter organisms possible.

Aim: The study was carried out to assess the microbial quality and safety of fermented camel milk product (Suusac) from North Eastern Kenya.

Methodology: Twenty-eight samples (n=28) of Suusac from different areas of the region sold in informal markets at Eastleigh in Nairobi were aseptically collected at the sales points. The quality and safety of the Suusac with reference to selected pathogens namely E. coli, S. aureus, Shigella, and Klebsiella spp was evaluated using the standard analytical methods.

Results: Escherichia coli were detected in all the samples while Staphylococcus aureus was detected in 63.09% of the samples analyzed. Shigella spp was detected in 88.1% of the samples analyzed and Klebsiella spp was detected in 77.4% of the samples. The mean log₁₀ counts for E. coli, S. aureus, Shigella, and Klebsiella spp were 3.135, 2.576, 2.784 and 3.138, CFUmL^-1, respectively. There is a potential public health concern posed by Suusac which is sold for direct consumption due to the presence of the life-threatening bacterial pathogens.

Conclusion: The Suusac being sold at Eastleigh market in Nairobi from North Eastern Kenya may be responsible for transmission of the pathogens to the consumers. Training on food hygiene, improving production technology, hygienic conditions and implementing the food legislations along the value chain can minimize the risk.

Aim: In order to ensure the accurate taxonomic identification of the lactic acid organisms that were previously isolated from spontaneously fermented yam for safety assessment and quality assurance purposes, phenotypic and genetic identification data were compared.

Study Design: Using the purposive sampling method, four microorganisms were characterized using molecular methods.

Place and Duration of Study:  Isolates of lactic acid microorganisms (2 bacterial and 2 fungal organisms) from spontaneously fermented yam in a previous study carried out in May 2016 were genetically identified using molecular methods. 

Methodology: Genomic DNA extracted from the test lactic acid microorganisms were used as templates in a PCR reaction, then, 16s rRNA and nuclear ribosomal internal transcribed spacer (ITS) genes were amplified for the bacterial and fungal isolates respectively. The polymerase chain reaction (PCR) products were electrophoresed on 2% agarose gel prepared with Tris Borate Ethylenediamintetraacetate (TBE) buffers stained with ethidium bromide. Subsequently, the ladder was used in order to determine the sizes of the corresponding amplicons captured on gel images in comparisons. Moreover, sequences of the PCR products were analyzed and the chromatograms subjected to BLAST (Basic Local Alignment Search Tool) analyses to identify the lactic acid organisms.

Results: The 2 bacterial isolates were identified as Bacillus subtilis (MK448227) and Bacillus pumilus (MK446418), on the other hand, the fungal isolates were identified as Aspergillus flavus (MK433604) and Aspergillus niger (MK430926). Discrepancies were observed when phenotypic identification data in an earlier report were compared with the molecular data from the present study. 

Conclusion: The present results underscore the limitations of phenotypic (biochemical) methods in characterizing organisms, particularly, organisms that may end up being used in food processing. Moreover, this is the first report of the novel organisms reported in the present study and makes further work into the development of starter organisms for the production of amala possible in the near future. In addition, proper identification helps in benchmarking the quality assurance and safety assessment of foods prepared using these organisms.

Chemical and nutritional properties of pumpkin (Curcubita pepo) seed proteins were studied. The seed was processed into defatted flour (CPF) which was further processed into Curcubita protein concentrate (CPC) and Curcubita protein isolate (CPI) by alkaline water/isoelectric precipitation. Chemical properties of the protein products were determined using standard methods of analysis. The amino acid profile was determined by an automated Technicon® liquid chromatography system. Protein digestibility was assessed in-vitro (IVPD) using trypsin-pepsin enzyme method while biological values were determined on the basis of their amino acid profile. Protein efficiency ratio (PER) was estimated according to a standard proposed regression equation. The seed proteins demonstrated high levels of crude protein (CPC=69.98% and CPI=74.15%), vitamin C (CPC=43.46 and CPI=52.36 mg/ml) and vitamin A (CPC=100.56 and CPI= 63.43 I.U/g) with low levels of thiamin and riboflavin. Both proteins showed low and similar (p>0.05) levels of sodium (0.14-0.18%), calcium (0.86-1.02%), magnesium (0.53-0.58%) and phosphorus (0.09-0.11%). Percentage ratios of essential to total amino acids obtained for CPC and CPI (44.24% and 45.50%, respectively) were greater than 36% which is considered adequate for an ideal protein. Protein biological values obtained for CPC and CPI respectively were: 95% and 53% (chemical score), 2.80 and 1.56 (PER} and 70.10% and 51.28% (essential amino acid index). CPC showed a better digestibility than CPI with IVPD value of 56.88%. Threonine and lysine were the most limiting amino acids in both protein products. All anti-nutrients evaluated were low and below allowable limits. In conclusion pumpkin seed proteins showed good biological values and could be used to improve the quality of other plant proteins or as a possible replacement for animal proteins in conventional foods.

This paper reviewed the common types of fad diets. Fad diets have an effective role in promoting weight loss, beneficial effects on body composition. Fad diets may protect against the development of obesity and related chronic diseases such as type two diabetes and coronary heart disease. Fad diets work simply because they restrict calorie intake, showing that the most important dietary concept of weight loss and maintenance is a decrease in caloric intake. Based on the contemporary studies on fad diets, the future concept for successful weight loss could run on the concept of energy density, which refers to the amount of energy in a given weight of food.