Optimization of processing conditions for vacuum frying of high quality fried plantain chips using response surface methodology (RSM)

Optimization of processing conditions (temperature 122 to 136°C, vacuum pressure 9.91 to 19.91 cmHg, and frying time 3 to 9 min) during vacuum frying of plantain chips was investigated using a Box-Behnken experimental design with response surface methodology (RSM). Models for various responses were developed and optimized frying conditions using numerical solutions were established. Optimized vacuum fried samples were compared with atmospheric fried samples based on the concept of equivalent thermal driving force (ETDF). Frying parameters had significant (p<0.05) effects on the moisture content, texture, and color with a coefficient of determination (R ²) for quadratic model responses varying between 0.53 and 0.99. Optimum vacuum frying conditions for plantain chips were a frying temperature of 133°C, vacuum pressure of 9.91 cmHg, and frying time of 6 min based on desirability concepts. Vacuum fried plantain chips had more acceptable sensory properties, based on ETDF values, than atmospheric fried samples.     

Making Sense of “Nonsense” and More: Challenges and Opportunities in the Genetic Code Expansion,in the World of tRNA Modifications

The evolutional development of the RNA translation process that leads to protein synthesis based on naturally occurring amino acids has its continuation via synthetic biology, the so-called rational bioengineering. Genetic code expansion (GCE) explores beyond the natural translational processes to further enhance the structural properties and augment the functionality of a wide range of proteins. Prokaryotic and eukaryotic ribosomal machinery have been proven to accept engineered tRNAs from orthogonal organisms to efficiently incorporate noncanonical amino acids (ncAAs) with rationally designed side chains. These side chains can be reactive or functional groups, which can be extensively utilized in biochemical, biophysical, and cellular studies. Genetic code extension offers the contingency of introducing more than one ncAA into protein through frameshift suppression, multi-site-specific incorporation of ncAAs, thereby increasing the vast number of possible applications. However, different mediating factors reduce the yield and efficiency of ncAA incorporation into synthetic proteins. In this review, we comment on the recent advancements in genetic code expansion to signify the relevance of systems biology in improving ncAA incorporation efficiency. We discuss the emerging impact of tRNA modifications and metabolism in protein design. We also provide examples of the latest successful accomplishments in synthetic protein therapeutics and show how codon expansion has been employed in various scientific and biotechnological applications.     

Proximate and Cholesterol Composition of Selected Fast Foods Sold in Nigeria

Fast foods consumption has been on the increase in Nigeria raising concerns about the nutritional and health implications. This study was carried out to determine the proximate composition and cholesterol contents of four commonly consumed fast foods (doughnut, chicken pie, roasted chicken, and Jollof rice) sold in Nigeria. Commonly consumed fast foods and most widely patronized fast food outlets were determined by a preliminary survey. There was a wide variation in the proximate composition and cholesterol contents of the food samples. Average dry matter ranged between 68.8 – 84.0 g while the range of values for ash, crude fibre, crude fat, crude protein and nitrogen free extract were 0.89 – 2.45%, 0.56 – 7.53%, 10.99 – 18.52%, 1.81 – 9.71% and 43.32 – 66.98% respectively. Energy content of the fast foods ranged between 304.9 and 400.8 Kcal/100 g. Cholesterol levels ranged between 10.40 – 117.80 (mg/100 g) in the food samples. This study has established the fact that fast foods are concentrated sources of energy, low fibre and high dietary cholesterol and could significantly contribute to dietary cholesterol intake with implications for cardiovascular health.     

Effect of Pre-Drying and Hydrocolloid Type on Colour and Textural Properties of Coated Fried Yam Chips

The effect of pre-drying and coating on colour and texture of yam chips were investigated. The colour parameters studied were lightness index (L*), hue angle (h) and browning index (BI). Peak force (PF) of penetration was observed for texture. Coating pick-up (amount of coating adhering to the samples) prior to frying was determined and moisture content of fried samples was also determined. The type of hydrocolloids used in the coating formulation had significant (p < 0.05) effect on coating pick-up, initial moisture content and texture of the chips; while samples that were not pre-dried had higher pick-ups and moisture contents. Pre-dried samples were darker brown in colour and harder in texture than samples that were not pre-dried as evidenced by their higher browning index and peak force values, respectively, thus enhancing the colour and texture of the chips.     

Production of exopolysaccharides by lactic acid bacteria isolated from traditional fermented foods in Nigeria

Lactic acid bacteria isolated from traditional fermented foods in Nigeria were investigated for their ability to produce exopolysaccharides (EPS). The test organisms were chosen after screening in a modified exopolysaccharide selection medium (mESM). The ability of the test organisms to produce EPS in whey medium (WM) and supplemented whey media (SWM I, SWM II) with combinations of lactose, KH₂PO₄, NH₄Cl, casamino acids, mineral salts and yeast extract was determined. Amongst the test isolates, only Leuconostoc mesenteroides (from sorghum ogi) and Lactobacillus plantarum (from maize ogi) demonstrated the highest form of EPS production. Adjustment of the pH of SWM II to 6.2 increased the viscosity relative to that of SWM I (5.7) that was not adjusted. The effect of incubation temperature showed that at 25 °C, the viscosity was higher for L. mesenteroides and L. plantarum than at 30 and 40 °C. However, the biomass yield was lower, the least lactose was utilized and less lactic acid was produced at this temperature. More galactose and glucose were liberated at 30 °C that at 25 and 40 °C. This paper suggested that the viscous nature of some traditional foods in sub-Saharan Africa may be partly due to excretion of polysaccharides during the fermentation processes.     

Opportunity to recycle chromium(VI) by in situ electro‐oxidation

BACKGROUND: Chemical oxidation is generally used to oxidise Cr(III) to Cr(VI) in aqueous effluents, but this leads to Cr(VI) solutions that are contaminated with oxidising agents, which reduces their recycle and reuse value. RESULTS: We now report an electrolytic method for the in situ oxidation of Cr(III). Complete oxidation of Cr(III) occurs anodically using an initial pH of 5.0 and a current of 3.0 A. CONCLUSIONS: Anodic oxidation is shown to achieve in situ oxidation of Cr(III) to Cr(VI) to permit the regeneration of Cr(VI) solutions for recycle in oxidising industrial processes. Copyright © 2008 Society of Chemical Industry     

Ionic liquids in the selective recovery of fat from composite foodstuffs

BACKGROUND: Ionic liquids (ILs) are able to dissolve a wide range of organic and inorganic molecules and have potential application in the separation and recovery of valuable components from wastes. The potential for ILs to separate sugar and fat from food waste is demonstrated using chocolate as a model system. RESULTS: The ILs 1‐(2‐cyanoethyl)‐3‐methylimidazolium bromide (cyanoMIMBr), 1‐propyl‐3‐methylimidazolium bromide (propylMIMBr), 1‐hexylpyridinium bromide (hexylPyrBr) and 1‐butyl‐3‐methylimidazolium chloride (butylMIMCl) were synthesised by microwave technology and fully characterised by mass spectrometry, thermogravimetric differential scanning calorimetery, thin layer chromatography, nuclear magnetic resonance and Fourier transform infrared spectroscopy. The solubilities of the fat and carbohydrate components in the ILs are reported for the two main ingredients in chocolate. CyanoMIMBr and propylMIMBr selectively solubilise sugar leaving the fat insoluble. Both cyanoMIMBr and propylMIMBr have been used to successfully separate sugars and cocoa butter fat from white, milk and dark chocolate and the Fourier transform infrared spectra and thermogravimetric differential scanning calorimeter profiles of the extracted fat samples are in good agreement with reference material data. CONCLUSIONS: The ILs cyanoMIMBr and propylMIMBr are successful in the separation and recovery of fat from white, milk and dark chocolate, as confirmed by FTIR and TG‐DSC data. Copyright © 2009 Society of Chemical Industry     

Selection of starters and a starter-mediated novel procedure for production of wara, a West African soft cheese

Summary Wara serves as an important protein source for people in West Africa. The ten most frequently isolated lactic acid bacteria from abomasum-soured milk samples were screened singly or in combinations as starter organisms for the production of wara . The screening was based on the bacteria's ability to produce lactic acid, diacetyl, β-galactosidase and an average weighted firm curd at 30 °C (6 h, 72 h). With lactic acid concentration of 10.0 g l⁻¹, β-galactosidase of 25.2 U mL⁻¹ and a firm curd weight of 16.0 g l⁻¹ milk at 30 °C, pH 5.1 after 6 h, a single-organism starter culture of Lactococcus lactis was chosen as the best suited. Compared with the commercial market samples, wara produced by this starter culture showed a 54% increase in percentage protein, 17.9% increase in ash, 23.6% increase in iron and a 150% increase in vitamin A content. Statistical analysis of sensory evaluation results showed a preference for the market sample only in terms of appearance and texture, while the starter-produced wara matched the market sample in terms of flavour and palatability. Treatment with 3% brine reduced microbial counts although dipping in 5% NaCl-in-whey gave better results in terms of the total viable count of mesophiles, psychrotrophs and coliforms compared with the untreated sample.