Constraints to utilization of the African nightshades and the effects of lactic acid fermentation on its nutritional and sensory qualities

A Thesis Submitted in Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Life Sciences of the Nelson Mandela African Institution of Science and TechnologyAfrican nightshades (ANS, Solanum nigrum complex) are among the most widely distributed and consumed indigenous vegetables in Tanzania. Several challenges hamper the utilization of ANS. This study sought to assess trends and constraints to ANS utilization in Kilimanjaro and Morogoro regions, Tanzania and also, to assess the effect of lactic acid fermentation on the nutritional and sensory quality of ANS. About 627 farmers' households were involved in the study. Quantitative and qualitative methods were employed to collect information. Semi structured questionnaires, focus group discussions and Key informants’ interviews were the methods of data collection. Solanum villosum and Solanum scabrum were fermented naturally and controlled fermentation using Lactobacillus plantarum and Leuconostoc mesenteroides. The results showed that ANS is mainly used as food (96.1%), animal feed (41.3%), and medicine (38%). On average, only 5% of ANS sales contributed to family income. The main constraints to ANS utilization include; pests and diseases (92.9%), lack of knowledge (58%), shortages of fertilizer (51%), shortages of pesticides (50%), inadequate means of transport (50.4%), lack of extension services (48%), improper postharvest handling (41.4%) and inadequate storage facilities (34%). Postharvest losses accounted for a 78.4% loss of ANS. There was minimal value addition on ANS, e.g., drying (5.3%) and fermentation (1.1%). Fermentation significantly reduced pH and increased titratable acidity. Fermentation increased β-carotene 2-5 times for both pickles. Vitamin C, chlorophyll and polyphenol were significantly reduced. Fermentation increased bioavailability of minerals (P, Ca, Fe and Zn). Knowledge should be given on good agricultural practices i.e., the proper use of pesticides, fertilizers, and quality seeds. Knowledge of the processing and preservation of ANS is necessary for farmers to improve utilization, reduce losses and ensure ANS availability. Fermentation can preserve ANS, with an increase in β-carotene and reducing antinutrients. Fermentation can be recommended to small-scale farmers, processors and households to improve their nutrition and livelihood

African nightshades (Solanum nigrum complex): The potential contribution to human nutrition and livelihoods in sub-Saharan Africa.

This research article published by John Wiley & Sons, Inc., 2021Achieving zero hunger in sub-Saharan Africa (SSA) without minimizing postharvest losses of agricultural products is impossible. Therefore, a holistic approach is vital to end hunger, simultaneously improving food security, diversity, and livelihoods. This review focuses on the African nightshades (ANS) Solanum spp. contribution to improving food and nutrition security in SSA. Different parts of ANS are utilized as food and medicine; however, pests and diseases hinder ANS utilization. African nightshade is rich in micronutrients such as β-carotene, vitamins C and E, minerals (iron, calcium, and zinc), and dietary fiber. The leaves contain a high amount of nutrients than the berries. Proper utilization of ANS can contribute to ending hidden hunger, mainly in children and pregnant women. Literature shows that ANS contains antinutritional factors such as oxalate, phytate, nitrate, and alkaloids; however, their quantities are low to cause potential health effects. Several improved varieties with high yields, rich in nutrients, and low alkaloids have been developed in SSA. Various processing and preservation techniques such as cooking, drying, and fermentation are feasible techniques for value addition on ANS in SSA; moreover, most societies are yet to adopt them effectively. Furthermore, promoting value addition and commercialization of ANS is of importance and can create more jobs. Therefore, this review provides an overview of ANS production and challenges that hinder their utilization, possible solutions, and future research suggestions. This review concludes that ANS is an essential nutritious leafy vegetable for improving nutrition and livelihoods in SSA

Effect of lactic acid fermentation on the nutritional quality and consumer acceptability of African nightshade

This research article was published Wiley Online Library, 2022African nightshade (ANS) is among many underexploited and neglected indigenous vegetables. This study assessed the effect of lactic acid fermentation (LAF) on nutritional and sensory quality in Solanum villosum (Sv) and Solanum scabrum (Ss). Spontaneously fermented (SF) and controlled fermented (CF) conditions using Lactobacillus plantarum LP90 and Leuconostoc mesenteroides LM58 were employed for 15 days and 120 h. From the fermented pickles, relish products were prepared using cooking oil and a variety of spices. The relish products were subjected to a consumer acceptability test. Results show a significant drop in pH to <3.5, increasing titratable acidity (TTA) to around 0.6 after 120 h and 15 days of CF and SF, respectively. LAF resulted in a 2.6–5 and 1.6–4.8-fold significant rise in β-carotene in pickles and their relish products. All pickles and relish products exhibited a significant decrease (p < .05) in vitamin C by 88.33%–95.90%. LAF significantly reduced total phenolic (26%– 43%) and Chlorophyll (16.45%–39.25%). On the other hand, LAF showed improvement in minerals content (P, Ca, Fe, and Zn) and reduction of tannin (76.27%–92.88%) and oxalate (77.33%–90%) levels. LAF relish products were highly preferred by the consumers, with S. villosum controlled fermented relish (SvCFR) leading. All fermented relishes were stable at ambient (27°C) and refrigeration (4°C) temperatures after 6 months of storage. Generally, LAF is an effective method for ANS preservation, with improved nutritional quality and safety. LAF can therefore be recommended to small-scale farmers, processors, and households for ANS preservation. Ultimately, this method enhances the nutrition and sensory quality, safety, and livelihood

Trends and constraints in the utilization of African nightshade (Solanum nigrum complex) in Tanzania: A case study of Kilimanjaro and Morogoro regions

African nightshade (ANS, Solanum nigrum complex) is among the most widely distributed and consumed indigenous vegetables in Tanzania. Several challenges hamper the utilization of ANS. This study sought to assess trends and constraints to ANS utilization in Kilimanjaro and Morogoro regions, Tanzania. Quantitative and qualitative methods were employed to collect information on ANS production, processing, and postharvest handling. Semi-structured questionnaires were used to collect quantitative data, whereas focus group discussion (FGDs) was used to collect qualitative data. A total of 627 farmers participated to fill questionnaire, and about eight FGDs with 6 - 10 participants conducted in Kilimanjaro and Morogoro. The results showed that 72.1% of farmers grow different ANS species, with Solanum scabrum vastly cultivated. Also, 79.4% of ANS farmers use irrigation, handheld hoe (97.6%), pesticides (70.7%), and fertilizer (64.8%) to produce ANS. African nightshade is mainly used as food (96.1%), animal feed (41.3%), and medicine (38%). On average, only 5% of ANS sales contributed to family income. Findings show that the main constraints to ANS utilization were pests and diseases (92.9%), lack of knowledge (58%), fertilizer shortages (51%), shortages of pesticides (50%), inadequate means of transport (50.4%), lack of extension services (48%), improper postharvest handling (41.4%) and inadequate storage facilities (34%). Postharvest losses accounted for 78.4% loss of ANS. Mitigation measures were; harvesting in small quantities (54.5%) and instant selling (61.9%) of fresh ANS. Drying (5.3%) and fermentation (1.1%) were the minimal value addition methods for ANS preservation. Moreover, boiling (63.0%) and frying (45.4%) were the typical methods of cooking ANS. More emphasis should be placed on good agricultural practices, providing knowledge to farmers, and supporting access to agricultural inputs such as pesticides, fertilizers, and quality seeds. Furthermore, knowledge of the processing and preservation of ANS is necessary for farmers to improve utilization, reduce losses, and ensure ANS availability. Also, research should focus on breeding local cultivar, which is resistant to pests and diseases