Fermentation of Colored Quinoa Seeds with Neurospora intermedia to Obtain Oncom-Type Products of Favorable Nutritional and Bioactive Characteristics Anna Starzy´ nska-Janiszewska, 1,† Bo˙ zena Stodolak, 1 Robert Duli´ nski, 1 Barbara Mickowska, 2 and Renata Sabat 3 ABSTRACT Cereal Chem. 0(0):1–6 In this research, colored quinoa seeds were subjected to a modified oncom-type processing (precooking followed by solid-state fermentation with Neurospora intermedia) to obtain convenient food products of im- proved parameters. Compared with the raw material, the products contained a higher level of protein (on average by 44%, with an advantageous essential amino acid profile) and fiber (by 71%) but a lower amount of inositol phosphates (by 50%, with an increased share of InsP 3 fraction in the profile). Fermented quinoa was enriched in carotenoids (6.5-fold) and riboflavin (fivefold). The antioxidant potential of oncom was also improved in respect to antiradical activity (on average by 39%) and reducing power. Of the red and black quinoa, the former substrate was processed into a product of better quality, containing a higher level of protein (214 g/kg dry matter [DM]), fiber (234 g/kg DM), carotenoids (81 mg/kg DM), and riboflavin (8 mg/kg DM), as well as antiradical activity (IC 50 in ABTS ×+ and DPPH × assay of 0.4 and 3 mg DM, respectively). This was associated with a 50% higher level of fungal glucosamine in this oncom. Therefore, the activity of N. intermedia can be considered beneficial for biotreatment of quinoa seeds. Traditional Indonesian solid-state fermentation of plant substrates with edible filamentous fungi allows a wide range of food products of valuable nutritional and functional parameters to be obtained. The substrates constitute plant seeds (soy and other legumes, as well as cereal grains and their mixtures) or wastes from the food industry such as oil cakes (after pressing an oil, e.g., from peanuts or co- conuts) and okara (after tofu production). The processing is based on a relatively brief (1–3 days) growth of mold inside and on the surface of a hydrothermally pretreated substrate. The obtained products can be classified as convenient, because their preparation for consumption is quick and easy (quick frying or cooking). Among fermented food products obtained by means of the procedure men- tioned above, the most typical are soy tempe and red oncom, made with the use of Rhizopus sp. (mainly R. oligosporus) and Neurospora intermedia, respectively. Generally, legume tempe is an internationally known food recognizable in Japan, the United States, and some Eu- ropean countries, whereas oncom is almost exclusive to Western Java (Owens et al. 2015). The aforementioned mold species can sometimes be used interchangeably; so-called black oncom is locally obtained in Indonesia with Rhizopus cultures, and some examples of Neurospora tempe have also been described in the literature (Shurtleff and Aoyagi 2010). A rather quick and easy process of these solid-state fermen- tations is suitable for introducing nontypical plant substrates and adjusting the procedure by using particular mold strains of certain enzymatic activities. Our previous research proved that good quality tempe-type products could be obtained from white and colored quinoa seeds fermented with R. oligosporus ATCC 64063. Those products were characterized by a more favorable nutritional composition and antioxidant potential than traditionally treated (namely, cooked until soft) seeds (Starzy´ nska-Janiszewska et al. 2016). However, to the best of our knowledge, a red oncom-type product from quinoa seeds has not been previously described in the literature. Quinoa is an ancient South American crop, of which nutritional and functional values have recently been rediscovered by scientists. Nowadays, a greater use of this pseudocereal is promoted by the FAO owing to its low environmental requirements and the advanta- geous composition of the seeds. Quinoa seeds contain gluten-free protein of well-balanced amino acid composition, good quality starch, dietary fiber, and polyunsaturated fatty acids. The level of phenolic compounds in quinoa seeds is higher than in traditional cereal grains, with phenolic acids (vanillic and ferulic) as major components (Mart´ ınez 2015). Apart from the advantages, this pseudocereal also contains antinutritional compounds, among which the most important are saponins, which impart a bitter taste, and phytate. The former are present in the pericarp and can be routinely removed by rinsing the seed in cold alkaline water or by mechanical abrasion. Phytate is located in the external layers as well as in the endosperm of quinoa seeds, so its decomposition must be performed by hydrothermal and/or enzymatic treatments (Jancurov´ a et al. 2009; Ismail et al. 2014). The aim of the present study was to characterize the nutritional parameters, phytate level, selected bioactive components, and an- tioxidant activity of oncom-type products from colored (red and black) quinoa seeds. The effects of a pretreatment (precooking) and the subsequent solid-state fermentation with N. intermedia on the substrate composition were analyzed, in comparison with the raw material. MATERIALS AND METHODS Quinoa seeds, debittered by polishing and washing, were pur- chased from a health-food store in Krak´ ow, Poland. The black seeds (Bolivian origin, packaged by Bio Planet) were medium sized of equivalent diameter, based on a sieve analysis: >2 mm (3%), 2 mm (96%), and <2 mm (1%). The red seeds (Peruvian origin, packaged by Batom) were small sized of equivalent diameter, based on a sieve analysis: >1 mm (6%), 1 mm (88%), and <1 mm (6%). N. intermedia DSM 1265 was grown on potato dextrose agar (12 days at 24°C). Precooking of Seeds. Quinoa seeds were rinsed and cooked for 15 min in tap water (1:3 m/v, acidified to pH 4.5–5 with lactic acid to ensure proper conditions for mycelium growth). Next, water was discarded, and the seeds were dried on a surface with a sterile cloth. Oncom-type fermentation was based on a traditional procedure (Owens et al. 2015) and modified by the authors. After cooling (<30°C), the precooked seeds were aseptically inoculated with fragments of N. intermedia mycelium and thoroughly mixed (5 min). Then the material was tightly packed in sterile petri dishes (diameter 10 cm, six replicates for every product) and incubated for 24 h at 30°C and >60% air humidity. After that time, the seeds were uni- formly overgrown with whitish mycelium, which was considered the end point of the first stage of the fermentation. Next, the petri dishes were opened, and the incubation was continued for 24 h, which † Corresponding author. E-mail: a.starzynska@ur.krakow.pl 1 Department of Food Biotechnology, Faculty of Food Technology, University of Agriculture in Krak´ ow, 30-149 Krak´ ow, Poland. 2 Malopolska Centre for Monitoring and Certification of Food, Faculty of Food Technology, University of Agriculture in Krak´ ow, 30-149 Krak´ ow, Poland. 3 Department of Carbohydrate Technology, Faculty of Food Technology, University of Agriculture in Krak´ ow, 30-149 Krak´ ow, Poland. http://dx.doi.org/10.1094/CCHEM-10-16-0264-R © 2017 AACC International, Inc. Vol. 0, No. 0, 2016 1