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Increased efficiency and productivity in agriculture are important to food security. Technical efficiency, as it affects sustainable production of selected underutilized indigenous vegetables, using innovative production practices or not, was analyzed. Primary data were collected from 300 respondents using questionnaires. The data were interpreted with a stochastic production frontier analysis and difference of means. A mean technical efficiency score of 74% for users versus 56% for nonusers incorporating innovative production practices in their operations indicated that users were more technically efficient. Opportunities exist to increase productivity in indigenous vegetable production through more efficient inputs utilization.

The aim of this work was to determine the antioxidant properties of aqueous extracts of vegetable leaf-fortified bread as well as estimate the contents of polyphenolic compounds. Enriched bread was produced from wheat flour fortified at 1, 2, and 3% (w/w) with dried leafy vegetable powders from Amaranthus viridis, Solanum macrocarpon, and Telfairia occidentalis. Gallic acid was the most abundant soluble polyphenol in the control bread and the content in the control bread was significantly higher (p < 0.05) than in all the fortified bread samples. Fortification of bread especially at 3% level resulted in significantly (p < 0.05) higher concentrations of other polyphenols (myricetin, catechin, quercetin, and rutin) compared to the control bread. The fortified bread extracts had significantly (p < 0.05) more effective antioxidants than the control for DPPH radical scavenging activity, ferric iron reducing antioxidant power, metal chelation, and inhibition of linoleic acid peroxidation. PRACTICAL APPLICATIONS: Bread is one of the consumed foods and could be used as a suitable carrier of bioactive compounds. Leafy vegetables contain high levels of polyphenols that could provide beneficial effects by contributing to improved health status of consumers. Therefore, incorporation of leafy vegetables into leavened bread could provide a means of enhancing polyphenol consumption. In this work, we showed that soluble polyphenols were enriched in vegetable-fortified bread. The polyphenol-rich extracts of the fortified bread demonstrated better free radical scavenging and inhibition of unsaturated fatty acid oxidation activities than the regular bread. Therefore, regular consumption of vegetable leaf-fortified bread could lead to reduced oxidative stress and associated chronic diseases in human beings. The vegetable leaf fortification could also serve as a suitable means of enhancing the shelf life of wheat bread.

Optimization of the yield, total phenolic content (TPC), and total antioxidant activities (TAA) of polyphenol concentrates extracted from Solanum macrocarpon leaves was studied using response surface methodology. The process variables investigated included extraction temperature (30, 50, and 70°C), extraction time (2, 4, and 6 h), and dried leaf powder : water ratio (1 : 10, 1 : 20, and 1 : 30 w/v). Box–Behnken design resulted in 15 experimental runs. The results showed the following optimum extraction conditions: temperature, 49.05°C; extraction time, 243 min; leaf powder : water ratio, 1 : 22 w/v. The optimized extraction conditions gave polyphenol concentrate yield, TPC, and TAA values of 24.94%, 421.09 mg GAE/g, and 23.81 mg AAE/g, respectively. Results of the in vitro antioxidant activities of the polyphenol concentrate showed 2, 2-diphenyl-2-picrylhydrazyl hydrate, metal chelating ability, and ferric reducing ability values of 76.78%, 80.22%, and 56.46 mg AAE/g, respectively. The study concludes that the experimental values compared closely with the predicted values, which indicates suitability of the model employed for polyphenol extraction optimization from dried S. macrocarpon leaves.