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Metabolite changes during natural and lactic acid bacteria fermentations in pastes of soybeans and soybean-maize blends.

Ng'ong'ola-Manani TA, Ostlie HM, Mwangwela AM, Wicklund T - Food Sci Nutr (2014)

Bottom Line: A 3.2% increase in sum of total amino acids was observed in 75SBS at 72 h, while decreases up to 7.4% in 100SBS at 48 and 72 h, 6.8% in 100S at 48 h and 4.7% in 75S at 72 h were observed.Maltose levels were the highest among the reducing sugars and were two to four times higher in LFP than in NFP at the beginning of the fermentation, but at 72 h, only fructose levels were significantly (P < 0.05) higher in LFP than in NFP.Both fermentation processes improved nutritional quality through increased protein and amino acid solubility and degradation of phytic acid (85% in NFP and 49% in LFP by 72 h).

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences P.O. Box 5003, 1430, Ås, Norway ; Department of Food Science and Technology, Lilongwe University of Agriculture and Natural Resources Bunda College Campus, P.O. Box 219, Lilongwe, Malawi.

ABSTRACT
The effect of natural and lactic acid bacteria (LAB) fermentation processes on metabolite changes in pastes of soybeans and soybean-maize blends was studied. Pastes composed of 100% soybeans, 90% soybeans and 10% maize, and 75% soybeans and 25% maize were naturally fermented (NFP), and were fermented by lactic acid bacteria (LFP). LAB fermentation processes were facilitated through back-slopping using a traditional fermented gruel, thobwa as an inoculum. Naturally fermented pastes were designated 100S, 90S, and 75S, while LFP were designated 100SBS, 90SBS, and 75SBS. All samples, except 75SBS, showed highest increase in soluble protein content at 48 h and this was highest in 100S (49%) followed by 90SBS (15%), while increases in 100SBS, 90S, and 75S were about 12%. Significant (P < 0.05) increases in total amino acids throughout fermentation were attributed to cysteine in 100S and 90S; and methionine in 100S and 90SBS. A 3.2% increase in sum of total amino acids was observed in 75SBS at 72 h, while decreases up to 7.4% in 100SBS at 48 and 72 h, 6.8% in 100S at 48 h and 4.7% in 75S at 72 h were observed. Increases in free amino acids throughout fermentation were observed in glutamate (NFP and 75SBS), GABA and alanine (LFP). Lactic acid was 2.5- to 3.5-fold higher in LFP than in NFP, and other organic acids detected were acetate and succinate. Maltose levels were the highest among the reducing sugars and were two to four times higher in LFP than in NFP at the beginning of the fermentation, but at 72 h, only fructose levels were significantly (P < 0.05) higher in LFP than in NFP. Enzyme activities were higher in LFP at 0 h, but at 72 h, the enzyme activities were higher in NFP. Both fermentation processes improved nutritional quality through increased protein and amino acid solubility and degradation of phytic acid (85% in NFP and 49% in LFP by 72 h).

No MeSH data available.


Changes in organic acids during fermentation. Samples coded 100S, 90S, and 75S represent naturally fermented pastes, while samples coded 100SBS, 90SBS, and 75SBS represent lactic acid-fermented pastes. Pastes are designated according to 100%, 90%, and 75% soybean composition, the remaining proportions being maize.
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fig01: Changes in organic acids during fermentation. Samples coded 100S, 90S, and 75S represent naturally fermented pastes, while samples coded 100SBS, 90SBS, and 75SBS represent lactic acid-fermented pastes. Pastes are designated according to 100%, 90%, and 75% soybean composition, the remaining proportions being maize.

Mentions: Citric, orotic, succinic, dl-lactic, uric, dl-pyroglutamic, propionic, α-ketoglutaric, oxalic, acetic and formic acids, and pyruvate were analyzed in the samples. However, detectable levels were only found in lactic, succinic, and acetic acids (Fig1). More lactic acid was produced in both NFP and LFP compared to acetic and succinic acids. Higher lactic acid productions implied lactic acid as the major end product of fermentation, a characteristic of LAB metabolism (Kandler 1983; Axelsson 1998; Klein et al. 1998; Holzapfel et al. 2001). Lactic acid in LFP was 2.5 to 3.5-fold higher than in NFP (Fig1A). Significantly high lactic acid production in LFP could mean higher LAB numbers in LFP resulting in dominant LAB metabolism compared to NFP. Alternatively, mixed fermentation processes of LAB and other microflora could be suggested for NFP. At 72 h, production of lactic acid was five to 16-fold and 19- to 30-fold higher than of succinic acid in NFP and LFP, respectively, while at the same time, lactic acid was one to twofold and 10- to 11-fold higher than acetic acid in NFP and LFP, respectively. The presence of acetic acid suggested heterofermentation in both LFP and NFP. Heterofermentative LAB produce acetic acid, ethanol, and CO2 in addition to lactic acid as products of fermentation (Kandler 1983). Heterofermentative and homofermentative LAB were identified in both the fermentation processes, and the former were dominant (data not shown).


Metabolite changes during natural and lactic acid bacteria fermentations in pastes of soybeans and soybean-maize blends.

Ng'ong'ola-Manani TA, Ostlie HM, Mwangwela AM, Wicklund T - Food Sci Nutr (2014)

Changes in organic acids during fermentation. Samples coded 100S, 90S, and 75S represent naturally fermented pastes, while samples coded 100SBS, 90SBS, and 75SBS represent lactic acid-fermented pastes. Pastes are designated according to 100%, 90%, and 75% soybean composition, the remaining proportions being maize.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4256583&req=5

fig01: Changes in organic acids during fermentation. Samples coded 100S, 90S, and 75S represent naturally fermented pastes, while samples coded 100SBS, 90SBS, and 75SBS represent lactic acid-fermented pastes. Pastes are designated according to 100%, 90%, and 75% soybean composition, the remaining proportions being maize.
Mentions: Citric, orotic, succinic, dl-lactic, uric, dl-pyroglutamic, propionic, α-ketoglutaric, oxalic, acetic and formic acids, and pyruvate were analyzed in the samples. However, detectable levels were only found in lactic, succinic, and acetic acids (Fig1). More lactic acid was produced in both NFP and LFP compared to acetic and succinic acids. Higher lactic acid productions implied lactic acid as the major end product of fermentation, a characteristic of LAB metabolism (Kandler 1983; Axelsson 1998; Klein et al. 1998; Holzapfel et al. 2001). Lactic acid in LFP was 2.5 to 3.5-fold higher than in NFP (Fig1A). Significantly high lactic acid production in LFP could mean higher LAB numbers in LFP resulting in dominant LAB metabolism compared to NFP. Alternatively, mixed fermentation processes of LAB and other microflora could be suggested for NFP. At 72 h, production of lactic acid was five to 16-fold and 19- to 30-fold higher than of succinic acid in NFP and LFP, respectively, while at the same time, lactic acid was one to twofold and 10- to 11-fold higher than acetic acid in NFP and LFP, respectively. The presence of acetic acid suggested heterofermentation in both LFP and NFP. Heterofermentative LAB produce acetic acid, ethanol, and CO2 in addition to lactic acid as products of fermentation (Kandler 1983). Heterofermentative and homofermentative LAB were identified in both the fermentation processes, and the former were dominant (data not shown).

Bottom Line: A 3.2% increase in sum of total amino acids was observed in 75SBS at 72 h, while decreases up to 7.4% in 100SBS at 48 and 72 h, 6.8% in 100S at 48 h and 4.7% in 75S at 72 h were observed.Maltose levels were the highest among the reducing sugars and were two to four times higher in LFP than in NFP at the beginning of the fermentation, but at 72 h, only fructose levels were significantly (P < 0.05) higher in LFP than in NFP.Both fermentation processes improved nutritional quality through increased protein and amino acid solubility and degradation of phytic acid (85% in NFP and 49% in LFP by 72 h).

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences P.O. Box 5003, 1430, Ås, Norway ; Department of Food Science and Technology, Lilongwe University of Agriculture and Natural Resources Bunda College Campus, P.O. Box 219, Lilongwe, Malawi.

ABSTRACT
The effect of natural and lactic acid bacteria (LAB) fermentation processes on metabolite changes in pastes of soybeans and soybean-maize blends was studied. Pastes composed of 100% soybeans, 90% soybeans and 10% maize, and 75% soybeans and 25% maize were naturally fermented (NFP), and were fermented by lactic acid bacteria (LFP). LAB fermentation processes were facilitated through back-slopping using a traditional fermented gruel, thobwa as an inoculum. Naturally fermented pastes were designated 100S, 90S, and 75S, while LFP were designated 100SBS, 90SBS, and 75SBS. All samples, except 75SBS, showed highest increase in soluble protein content at 48 h and this was highest in 100S (49%) followed by 90SBS (15%), while increases in 100SBS, 90S, and 75S were about 12%. Significant (P < 0.05) increases in total amino acids throughout fermentation were attributed to cysteine in 100S and 90S; and methionine in 100S and 90SBS. A 3.2% increase in sum of total amino acids was observed in 75SBS at 72 h, while decreases up to 7.4% in 100SBS at 48 and 72 h, 6.8% in 100S at 48 h and 4.7% in 75S at 72 h were observed. Increases in free amino acids throughout fermentation were observed in glutamate (NFP and 75SBS), GABA and alanine (LFP). Lactic acid was 2.5- to 3.5-fold higher in LFP than in NFP, and other organic acids detected were acetate and succinate. Maltose levels were the highest among the reducing sugars and were two to four times higher in LFP than in NFP at the beginning of the fermentation, but at 72 h, only fructose levels were significantly (P < 0.05) higher in LFP than in NFP. Enzyme activities were higher in LFP at 0 h, but at 72 h, the enzyme activities were higher in NFP. Both fermentation processes improved nutritional quality through increased protein and amino acid solubility and degradation of phytic acid (85% in NFP and 49% in LFP by 72 h).

No MeSH data available.