Implementation of good manufacturing practices (GMP) to improve the quality of smoked fish (Scombercolias).

For several years, fish smoking has been the widely adopted processing method among artisanal fish smokers located along the coastal zones in many parts of West Africa including Ghana. However, several issues pertaining to biochemical and microbiological contaminants still remain, mainly because of the suboptimal, unhygienic fish handling during the processing. To help curtail the problem, we developed and implemented a simple good manufacturing practice (GMP) system for experimentation at two local fish smoking facilities (Facility A, FA; Facility B, FB) to assess the effectiveness for improving the quality of smoked fish. The implementation of GMP did not affect the physical properties of the smoked fish but improved the peroxide value, total volatile base nitrogen, polyaromantic hydrocarbons and histamine levels. The total aerobic counts decreased from 3.96 ± 0.12 cfu/g to 1.52 ± 0.28 cfu/g (FA) or from 4.10 ± 0.2 cfu/g to 1.85 ± 0.85 cfu/g, (FB). The coliforms and Escherichia coli decreased respectively from 1.69 ± 0.12 cfu/g and 1.15 ± 0.21 cfu/g (FA) and from 1.74 ± 0.37 cfu/g and 1.24 ± 0.37 cfu/g, (FB) to below detection (no observed colony) after introducing the single use of potable water, use of smoking oven and fish core temperature of 108.1 ± 7.5 °C and 82.5 ± 3.9 °C, respectively for 2 h, wearing of safety apparels, drying and cooling of smoked fish under nets, and the use of waste disposal bins. The results show that sensitization and training of fish smokers in GMP may be relevant for improving the microbial and overall quality of smoked fish.

Effects of sprouting duration on the nutrient, functional, and phytochemical properties of tiger nut flour, and the sensory properties of bread made thereof.

The influence of sprouting on tiger nut's (TN) nutritional, functional, and phytochemical quality was examined, and the flour used for bread making to evaluate the feasibility as a functional ingredient. TN was sprouted and sampled at 3 days intervals for 12 days, dried and milled into flour and analyzed. Subsequently, 25% of wheat flour (WF) was replaced with the 9 days-sprouted TN flour for bread. Sprouting for 9 days increased the protein content from 9.19 ± 0.04 to 9.79 ± 0.15 g/100 g dry matter (DM), fiber from 6.75 ± 0.16 to 9.27 ± 0.44 g/100 g DM, and ash from 2.34 ± 0.10 to 2.70 ± 0.06 g/100 g DM but decreased fat content from 26.10 ± 0.18 to 23.18 ± 0.43 g/100 g DM and soluble sugar from 33.13 ± 1.25 to 23.75 ± 1.44 °Bx. We observed increases in the polyphenols (94.16 ± 6.43-214.23 ± 6.98 mg GAE/100 g) and ascorbic acid (26.66 ± 0.17-65.13 ± 0.19 mg AE/100 g) and decreases in the cyanogenic glycosides (273.79 ± 0.37-231.54 ± 3.53 mg/100 g) and oxalates (19.04 ± 1.14-5.65 ± 0.93 mg/100 g) contents. Sprouting decreased the particle size and increased the water retention and swelling power of TN flour. WF bread was described as stretchy, sweet, and creamy, whereas sprouted TN bread was brown, nutty, and wheat-like. Consumer acceptance for the sprouted TN bread was comparable to WF bread, showing the possible application in bread making. PRACTICAL APPLICATION: The outcome of the study could help to exploit the nutri-functional and phytochemical benefits of sprouted TN in the baking industry for producing acceptable products. This would enhance the utility of TN for food in regions where TNs grows.

Influence of Partially Substituting Wheat Flour with Tiger Nut Flour on the Physical Properties, Sensory Quality, and Consumer Acceptance of Tea, Sugar, and Butter Bread.

Tiger nut is a valuable source of fiber, lipids, minerals, and carbohydrates. However, avenues for incorporating tiger nuts into food remain underexplored, especially in several tropical countries where the plant grows well. The current study investigated the effects of partially substituting wheat flour (WF) with tiger nut flour (TNF) on the physical and sensory properties of different bread types to evaluate the more amenable system for tiger nut incorporation. The substitution was done at WF:TNF ratio of 100 : 0, 90 : 10, 85 : 15, 80 : 20, 75 : 25, and 70 : 30 for butter bread (Bb), tea bread (Tb), and sugar bread (Sb). The results show that WF substitution with TNF increased bread brownness and color saturation and decreased lightness, showing the highest impact on Sb, followed by Tb and Bb. Additionally, bread-specific volume decreased significantly after 20% (Bb), 25% (Tb), and 30% (Sb) TNF substitution. Furthermore, substituting WF with 30% TNF increased crumb hardness from approx. 1.87 N to 3.64 N (Bb), 3.46 N to 8.14 N (Tb), and 6.71 N to 11.39 N (Sb) and caused significant increases to 17.80 N (Tb) and 21.08 N (Sb) after 3 d storage. Only a marginal effect on storage hardness (4.32 N) was observed for Bb. Substituting WF with 10% TNF for Bb or 25% TNF for Tb led to significantly higher consumer (N = 56) scores for all attributes and overall acceptability. However, no significant effect on the overall acceptability of Sb was observed. Flash profiling showed frequently used descriptors for Bb as firm, moist, buttery, smooth, and astringent. After 10% TNF substitution, descriptors were chewy, firm, sweet, porous, dry, and caramel, and that of 30% TNF were grainy, chocolate, brown, nutty, and flaky. Substituting WF with TNF increased the lipids, fiber, and minerals content but decreased the protein and carbohydrate contents of bread. TNF substitution led to different physical and sensory effects depending on bread type, showing that Bb with 10% or Tb with 25% TNF is more comparable with the overall acceptance quality of 100% WF. The study is relevant for utilizing tiger nuts as an ingredient in bread products.

Multi-objective experimental design for (13)C-based metabolic flux analysis.

(13)C-based metabolic flux analysis is an excellent technique to resolve fluxes in the central carbon metabolism but costs can be significant when using specialized tracers. This work presents a framework for cost-effective design of (13)C-tracer experiments, illustrated on two different networks. Linear and non-linear optimal input mixtures are computed for networks for Streptomyces lividans and a carcinoma cell line. If only glucose tracers are considered as labeled substrate for a carcinoma cell line or S. lividans, the best parameter estimation accuracy is obtained by mixtures containing high amounts of 1,2-(13)C2 glucose combined with uniformly labeled glucose. Experimental designs are evaluated based on a linear (D-criterion) and non-linear approach (S-criterion). Both approaches generate almost the same input mixture, however, the linear approach is favored due to its low computational effort. The high amount of 1,2-(13)C2 glucose in the optimal designs coincides with a high experimental cost, which is further enhanced when labeling is introduced in glutamine and aspartate tracers. Multi-objective optimization gives the possibility to assess experimental quality and cost at the same time and can reveal excellent compromise experiments. For example, the combination of 100% 1,2-(13)C2 glucose with 100% position one labeled glutamine and the combination of 100% 1,2-(13)C2 glucose with 100% uniformly labeled glutamine perform equally well for the carcinoma cell line, but the first mixture offers a decrease in cost of $ 120 per ml-scale cell culture experiment. We demonstrated the validity of a multi-objective linear approach to perform optimal experimental designs for the non-linear problem of (13)C-metabolic flux analysis. Tools and a workflow are provided to perform multi-objective design. The effortless calculation of the D-criterion can be exploited to perform high-throughput screening of possible (13)C-tracers, while the illustrated benefit of multi-objective design should stimulate its application within the field of (13)C-based metabolic flux analysis.