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

Abstract

African 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.

Pure and Co-Fermentation of Quinoa Seeds by Limosilactobacillus fermentum and Lacticaseibacillus rhamnosus: Bioactive Content, Antidiabetic and Antioxidant Activities

“…It was also reported that pH strongly affected the degradation of vitamin C, so that vitamin C was most stable at pH 3.5 and least stable at pH 5.5 [38]. These achievements are consistent with the results of Sangija et al [40], who showed a substantial decrease in the vitamin C content of African nightshade during controlled and spontaneous fermentation by Leuconostoc mesenteroides and L. plantarum. Similarly, different researchers detected vitamin C loss after the fermentation of lupini beans, cowpea, and pigeon pea [34,41,42].…”

Certain Fermented Foods and Their Possible Health Effects with a Focus on Bioactive Compounds and Microorganisms

“…However, it has also been suggested that it may have health-promoting effects [265]. It has been shown that lectin, phytate, tannin, and oxalate levels decrease as a result of fermentation compared to fresh produce [266][267][268]. As a result of lactic acid fermentation in the African nightshade plant, the tannin level decreased by 76.27-92.88%, and the oxalate level decreased by 77.33-90% [267].…”

Prospective Role of Indigenous Leafy Vegetables as Functional Food Ingredients

“…Increased the amounts of 3-caffeoylquinic, 4-caffeoylquinic and 5-caffeoylquinic acids, Ekaempferol-3-O-rutinoside, chlorogenic acid, caffeoylmalic acid and quercetin-3-O-xylosyl-rutinoside [14] Nightshade pickle and relish Fermentation Improved the β-carotene content of both products [186] Jew's mallow Cooking Improved mineral content (phosphorous, potassium, calcium, magnesium, sodium and micro minerals (iron, manganese, zinc)) of the leaves [187] Enhanced protein, ash and dietary (soluble and insoluble) fibre [187] Improved cellulose and hemicellulose of the leaves and enhanced essential amino acids except phenylalanine [187] Chinese cabbage Blanching in 5% lemon juice Increased total chlorophyll retention [128] Increased TPC, FRAP and TEAC [128] Improved quinic and ferulic acids [128] Improved levels of kaempferol-dihexoside, sinapoyl malate, rutin, isorhamnetin-O-dihexoside and kaempferol-3-O-hydroxyferuloyl-trihexoside in the leaves [128] Stir frying Improved levels of kaempferol-3-O-hydroxyferuloyl-trihexoside, kaempferol-dihexoside, sinapoyl malate, rutin and isorhamnetin-O-dihexoside [128] Fermentation Increased β-carotene content [188] Improved mineral content (iron, zinc, calcium, potassium, copper and nickel) [188] Pumpkin leaves Boiling Improved the bioaccessibility of most polyphenols apart from methylquinic acid, cis-4-feruloylquinic acid and phenethyl rutinoside [189] Stir frying…”