Preparation and Characterization of Black Oncom Flour Used in the Development of a Vegetarian Spread

Abstract

Introduction: Black oncom is a traditional fermented food from Indonesia. The aim of this study was to develop a vegetarian spread made from soybean flour (MH1), peanut flour (MH2), and black oncom flour (MH3), and to compare their physicochemical, nutritional, and sensory properties.

Materials and Methods: Two spreads were prepared: MU2, formulated with soybean flour (MH1) and peanut flour (MH2), and MU3, formulated with soybean flour (MH1) and black oncom flour (MH3). Official AOAC methods and instrumental techniques were used to characterize the f lours and spreads, with all analyses performed in triplicate. Microbiological safety, total aflatoxin content, and sensory acceptability were evaluated using a panel of 34 untrained assessors. Statistical analysis was performed using the Student’s t-test (p < 0.05).

Results: MH3 was obtained by inoculating roasted peanuts with Rhizopus spp. var. oligosporus. The proximate composition of MH2 and MH3 (g/100 g) was as follows: protein, 27.1 ± 0.1 and 23.0 ± 0.2; total fat, 47.6 ± 0.2 and 44.7 ± 0.6; carbohydrates, 10.0 ± 0.5 and 18.8 ± 0.5; total dietary fiber, 9.5 ± 0.2 and 9.2 ± 0.2; phenolic compounds (mg/100 g), 149 ± 15.6 and 134 ± 5.7; and phytic phosphorus (g/100 g), 0.4 ± 0.3 and 0.5 ± 0.3, respectively. For spreads MU2 and MU3, the following values were obtained, respectively: ash, 2.1 ± 0.02 and 1.9 ± 0.03; moisture, 55.3 ± 0.5 and 58.0 ± 0.5; protein, 12.1 ± 0.5 and 10.7 ± 0.5; total fat, 17.3 ± 0.5 and 14.5 ± 0.3; carbohydrates, 6.6 ± 0.5 and 6.7 ± 0.5; dietary fiber, 6.7 ± 0.3 and 8.3 ± 0.3; pH, 6.8 ± 0.02 and 6.3 ± 0.01; and water activity (Aw), 0.98±0.01 in both products. Phenolic compounds (mg/100 g) were 130 ± 21.2 and 123 ± 5.7, while phytic phosphorus (g/100 g) was 0.6 ± 0.3 and 0.4 ± 0.3, respectively. The fatty acid profile of MU3 showed 73.9% oleic acid, 2.5% linoleic acid, and 0.1% linolenic acid. MU3 was microbiologically safe, with total af latoxin levels below 1.6 μg/kg. Colorimetry and texture analysis were consistent with the sensory evaluation. MU3 was described as soft, moist, creamy, dark, with a smoky, umami, spicy, and intense odor and flavor.

Conclusion: The black oncom spread is a ready-to-eat plant-based product that is microbiologically safe and sensory acceptable. Peanut fermentation provides nutritional benefits, making this spread an innovative and acceptable alternative for complementing the daily diet.