Jackfruit Seed Powder Boosts Protein and Vitamins in Maize Porridge, but Only at Low Levels Do Tasters Approve

Kenyan food scientists have turned an agricultural waste product into a functional ingredient for one of East Africa’s most important staples, and the trade-offs they measured are striking. In a laboratory study published in Food Science & Nutrition, researchers fortified both sifted and whole white maize flour with jackfruit seed powder at substitution levels of 10, 20, 30, and 40 percent, then cooked the blends into stiff maize porridge, the dish known regionally as ugali. Yet a trained sensory panel preferred the porridge only at the lowest fortification level, and acceptability fell steadily as the seed powder proportion climbed.

The motivation is grounded in a well-documented nutritional problem. White maize is a primary food source for many people in sub-Saharan Africa, particularly Kenya, and maize-based stiff porridge supplies limited quantities of essential amino acids such as lysine and tryptophan, is low in B-complex vitamins, and offers limited bioavailability of microminerals such as iron and zinc. Over-reliance on maize without dietary diversification therefore increases the risk of nutritional deficiencies in communities that depend on it as their principal food. The researchers argued that fortifying maize with locally available, nutrient-rich by-products such as jackfruit seeds could address this gap without requiring consumers to change what they eat.

Jackfruit, the largest of the edible fruits in the Moraceae family and capable of weighing up to 50 kilograms, is composed of pulp, seeds, and rind. The seeds are typically discarded as waste, even though they are an excellent source of protein, vitamins, dietary fiber, and minerals, and contain bioactive compounds with reported antimicrobial, antioxidant, and other activities. Because the seeds lack significant flavor and are considered a waste stream, the team viewed them as a cost-effective fortification candidate. Previous work had not systematically examined how jackfruit seed powder interacts with white maize flour in stiff porridge, which the authors identified as a significant gap in functional food development.

The experimental materials came from single sources in Kenya. Six mature, ripe jackfruits, each weighing approximately 20 kilograms and all from the same tree, were purchased from a farmer in Kwale County, while 10 kilograms of white maize grain came from a farm in Homa Bay County. The seeds were peeled, soaked in sterile distilled water for 24 hours to remove the brown covering on the cotyledons, sliced, sun-dried for four days, and milled into powder. The maize was processed into whole and sifted flour at a commercial mill in Nairobi. For each flour type, five formulations were prepared in triplicate: an unfortified control and blends containing 10 to 40 percent jackfruit seed powder.

The stiff porridge itself was cooked under standardized conditions. Approximately 100 grams of each flour was progressively added to 200 milliliters of boiling water while stirring continuously over medium heat for about seven minutes, then turned and cooked on low heat for a further three minutes. Proximate composition was determined by AOAC methods, including oven-drying for moisture, Soxhlet extraction for fat, Kjeldahl digestion for protein, and acid-alkali hydrolysis for crude fiber, with carbohydrate calculated by difference. Total phenolic content was measured by the Folin-Ciocalteu method, minerals by inductively coupled plasma optical emission spectroscopy and flame emission spectrophotometry, and vitamins B1 and B6 by high-performance liquid chromatography. All analyses were run in triplicate and compared by one-way ANOVA with Tukey’s post hoc test.

The compositional results showed a consistent dose-dependent pattern. Jackfruit seed powder itself contained 15.49 percent protein, 3.82 percent ash, 3.40 percent crude fiber, and 2.22 milligrams of phenolics per gram, along with 311.56 milligrams per kilogram of thiamine and 66.65 milligrams per kilogram of vitamin B6, far exceeding the maize flours on most of these measures. Sifted maize flour, by contrast, had 8.03 percent protein, 0.70 percent ash, and no detectable thiamine. Blending shifted the porridge accordingly: stiff porridge from sifted maize flour rose from 1.66 percent protein to 5.95 percent at the highest fortification, and whole maize porridge rose from 1.24 percent to 5.98 percent. Fiber in the cooked porridge climbed from 1.30 percent to 2.49 percent in the sifted series and from 1.33 percent to 2.54 percent in the whole maize series, while fat content fell, reflecting the naturally low fat content of the seeds.

Cooking, however, took a measurable toll. Thiamine in the fortified flours ranged up to 134.56 milligrams per kilogram in the sifted series and 119.17 milligrams per kilogram in the whole maize series, but decreased significantly in the corresponding stiff porridge, consistent with the known sensitivity of B vitamins to heat. Vitamin B6 followed the same pattern, dropping from as much as 56.32 milligrams per kilogram in fortified sifted flour to 17.14 milligrams per kilogram in the cooked porridge, and no B6 was detectable in porridge made from unfortified maize. Mineral concentrations also declined after cooking; the authors attribute this apparent loss mainly to dilution, since porridge was prepared at a two-to-one water-to-flour ratio and analyzed on a wet weight basis. Even so, porridge from the 40 percent blends retained substantially more calcium, copper, iron, potassium, magnesium, and manganese than porridge from unfortified maize.

Phenolic content told a similar story of partial retention. Uncooked fortified flours gained phenolics progressively with jackfruit seed powder proportion, and although cooking significantly reduced total phenolic content, the highest-fortification porridges still held 1.95 milligrams per gram in the sifted series and 2.16 milligrams per gram in the whole maize series, compared with just 0.17 and 0.58 milligrams per gram in unfortified porridge. The authors note that phenolic compounds are antioxidants but can also hinder mineral uptake and protein digestion at high concentrations, and they suggest that thermal processing may mitigate some anti-nutritional effects while preserving part of the beneficial fraction.

Sensory evaluation set the practical limit. A panel of 31 trained Food Science and Technology students rated each porridge on a five-point hedonic scale across aroma, color, texture, taste, appearance, mouthfeel, and overall acceptability. Unfortified porridge from both flour types scored highest, with mean ratings above 3.40 on most attributes. The 10 percent blends, SMF plus 10 percent jackfruit and WMF plus 10 percent jackfruit, were the most acceptable fortified formulations, with overall acceptability scores of 3.10 and 2.85 respectively. Beyond that, scores declined steadily: overall acceptability fell to 1.96 for both 40 percent blends, and taste dropped as low as 1.54. The panelists reported that the seed powder introduced a grainy texture that negatively affected mouthfeel, and the authors suggest that differing starch and protein structures in jackfruit seeds may alter gelatinization and water absorption, producing a less cohesive product, while natural phytochemicals may contribute bitterness at higher levels.

The authors conclude that 40 percent jackfruit seed powder produced the most nutrient-rich stiff porridge, while 10 percent offered the best balance of enhanced nutrition and sensory acceptability, delivering measurable gains in protein, fiber, vitamins, and minerals without the steep drop in palatability seen at higher substitution rates. They frame the approach as a way to transform low-value jackfruit seed waste into a functional ingredient, noting that the seeds are available without seasonal limitation and that the preprocessing steps are simple enough for community-scale or industrial adoption. The team also flagged the limits of the work: future studies should evaluate product stability, characterize the amino acid profile, assess micronutrient contribution and mineral bioavailability, and test acceptability in broader and more representative consumer groups beyond the trained student panel used here.

Subject of Research: Fortification of whole and sifted maize flour with jackfruit seed powder for stiff maize porridge

Article Title: Nutritional Enrichment and Sensory Profiles of Whole and Sifted Maize Flours Fortified With Jackfruit Seed Powder for Stiff Porridge Preparation

Article References: Odhoch, F. O., Ojwang, R. A., Mwaniki, M. W., Mbatia, B. N., Gitiri, M. E., Muge, E. K., & Nyaboga, E. N. (2026). Nutritional Enrichment and Sensory Profiles of Whole and Sifted Maize Flours Fortified With Jackfruit Seed Powder for Stiff Porridge Preparation. Food Science & Nutrition, 14(10), Article e72478. https://doi.org/10.1002/fsn3.72478

Image Credits: AI Generated

DOI: 10.1002/fsn3.72478

Keywords: jackfruit seed powder, maize flour, food fortification, stiff porridge, ugali, protein content, B vitamins, minerals, phenolic content, sensory evaluation, Kenya, food science