Effect of processing methods on the micronutrient profile, colour, and anti- nutritive components of justicia heterocarpa (mwidu)
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Date
2025-02-05
Journal Title
Journal ISSN
Volume Title
Publisher
European Journal of Nutrition & Food Safety
Abstract
Justicia heterocarpa (mwidu) is a popular indigenous leafy vegetable picked wild in rural regions of
Morogoro, Tanzania, during the wet seasons. This research examined the impact of processing on
micronutrients, total phenols, and anti-nutrient content. The fresh leaves (FL) underwent direct
shade drying (UBLDDR), blanched shade drying (BLDR), blanched oven drying (BLDO),
fermentation (FFL), and gas and microwave cooking (FLCO5, FLCO10, and FLMCO2). Vitamins,
chlorophyll, minerals, phenolic compounds, and anti-nutrients were analyzed. All laboratory
experiments adhered to procedures and guidelines. The pH dropped more significantly to <3.5 in a 3% salt-3% sugar brine solution with 1.328 ± 0.006 mg/100 g of lactic acid compared to its
counterpart. Blanched leaves dried in 5 days, but unblanched leaves took 15 days. Fermented
samples demonstrated a notable reduction in total chlorophyll concentration (0.0964 ± 0.075 mg/g)
compared to other processing techniques. The nutritional and anti-nutritional composition of
Justicia heterocarpa showed significant change (P < 0.05) depending on processing methods. The
results indicated a significant loss of vitamin C in the fermented and ten-minute cooked samples, at
74.57% and 61.64%, respectively.Cooked FLMCO2 (107.4%, 11.29 ± 0.03 mg/100g) and FLCO5
(86.26%, 10.51 ± 0.02 mg/100g) exhibited more than a two-fold increase in beta-carotene
compared to fresh leaves (3.67 mg/100g). In comparison to alternative processing procedures,
samples cooked for 10 minutes exhibited significant mineral leaching, whereas unblanched direct
shade drying preserved the highest mineral concentration. Fermented samples (532.83 ± 14.91
GAE/100 g) exhibited a 64.19% increase in total Phenolic compounds compared to fresh leaves
(190.83 ± 14.91 GAE/100 g). Nonetheless, tannins increased by 68.1% (254.44 ± 7.45 GAE/100g)
in the fermented samples. Samples exposed to extended cooking (17.8 ± 3.17 mg/100 g) and
fermentation (40.28 ± 3.34 mg/100 g) exhibited the lowest levels of phytates. The oxalate
concentration was significantly decreased in the cooked samples. Justicia heterocarpa may serve
as a sustainable food supply in areas of Tanzania experiencing nutritional deficits.
Description
Journal Article
Keywords
Anti-nutrients, Justicia heterocarpa, micronutrients, Processing, ndigenous leafy vegetables
Citation
Swai, Zenorina Aloyce, Frida Albinus Nyamete, and Valerian. C. K. Silayo. 2025. “Effect of Processing Methods on the Micronutrient Profile, Colour, and Anti-Nutritive Components of Justicia Heterocarpa (mwidu)”. European Journal of Nutrition & Food Safety 17 (2):107-24. https://doi.org/10.9734/ejnfs/2025/v17i21637.