Fermentation of Seeds of Teff (Eragrostis teff), Grass-pea (Lathyrus sativus), and Their Mixtures:  Aspects of Nutrition and Food Safety

Abstract

Fermentation of pure teff (Eragrostis teff), pure grass-pea (Lathyrus sativus), and their mixtures, 9:1 and 8:2 (teff/grass-pea) has been done at two temperatures (room temperature and 35 degrees C) in duplicate using the strains of Lactobacillus plantarum, for bacterial fermentation, and Aspergillus oryzae and Rhizopus oligosporus in succession for solid-state fungal fermentation as inocula. In addition, the natural or spontaneous and back-slopping methods of bacterial fermentation have been done on the above four substrate groups. The pH and essential amino acid profiles of the different fermentation processes were compared. The back-slopping in teff at a temperature of 35 degrees C gave the sharpest pH drop. All fermentations done at 35 degrees C showed a steeper slope in their pH versus time plot compared to their room temperature counterpart. Fungal fermentation gave an improved amino acid profile for the essential ones in all of the substrate groups, except in pure grass-pea. Fermented teff/grass-pea (8:2) in this fungal fermentation has been found to be quite comparable in essential amino acid profile to an ideal reference protein recommended for children of 2-5 years of age. None of the bacterial fermentations produced a net change in their essential amino acid profile in any of the substrate groups investigated. Solid state fungal fermentation on pure grass-pea using the fungal strains R. oligosporous and A. oryzae in succession has shown that the neurotoxin beta-N-oxalyl-alpha,beta-diaminopropionic acid (beta-ODAP) in grass-pea has been removed by 80% on average for the high-toxin variety and by up to 97% for the low-toxin variety as determined by an improved chromatographic method with bioelectrochemical detection coupled on-line with refractive index detection.

Phytic acid degrading lactic acid bacteria in tef-injera fermentation

“…The high numbers of LAB are assumed to be responsible for the relatively high lactic and acetic acid production and thereby outcompeting non-acid-tolerant species. The fall in pH below 4, reported from different Ethiopian injera fermentations (Baye et al, 2013;Yigzaw et al, 2004) was similarly observed in our model set-up.…”

“…Before the batter is finally poured onto a clay plate and baked, a so-called "absit" is prepared by boiling a portion of the batter with water and adding it back to the fermenting batter, ensuring the desired textural quality of the baked injera pancake. Due to the use of ersho, the pH drops rapidly (Yigzaw et al, 2004) and reaches values below pH 4 within hours (Baye et al, 2013;Stewart and Getachew, 1962). As would be expected with acidification, microbial analysis of tef-injera batter has reported lactic acid bacteria (LAB) to be the major fermentative microbes accompanied by yeast, Enterobacteriaceae and Bacillus spp., but the latter was detected to a lesser extent (Nigatu and Gashe, 1998).…”

Teff (Eragrostis tef) as a raw material for malting, brewing and manufacturing of gluten-free foods and beverages: a review

“…The overall amino acid profile of teff can be regarded as well-balanced (Table 2). Yigzaw et al (2004) reported that spontaneous fermentation of teff caused decreases in threonine, valine, isoleucine, and lysine contents by 30, 8, 20 and 17 %, respectively. According to this research finding, amino acids such as leucine, phenylalanine, and histidine showed no significant change, whereas methionine was increased by 90 %.…”

“…According to this research finding, amino acids such as leucine, phenylalanine, and histidine showed no significant change, whereas methionine was increased by 90 %. Fermentation with Lactobacillus plantarum (lactic acid bacteria) caused decreases in threonine, isoleucine, lysine, and valine by 28, 14, 17, and 6 %, respectively (Yigzaw et al 2004). They found that fermentation with lactic acid bacteria increased the amounts of leucine (12 %) and methionine (110 %), whereas phenylalanine and histidine remained practically the same.…”

Total and Partial Substitution of the Local Grass Pea Seed Lathyrus sativa Processed by Different Methods by Soy Bean Meal Glycine max in Small Common Carp Cyprinus carpio L. Diets

“…The results of the present study also indicated that bacterial fermentation improves the nutritive value of GPS [22]. Nutritionally, it is tasty and protein-rich [6], but the presence of a variety of anti-nutritional factors hinders its free nutritional utilization [5]. Tannin, phytic acid and β-ODAP could be significantly reduced in grass pea fermented with Bacillus sp.…”