Microbial population and physico-chemical composition of an African Fish based flavouring agent and taste enhancer

Abstract

Sixty samples of a traditional flavouring agent and taste enhancer (FATE) locally referred to asLanhouin obtained by spontaneous fermentation of cassava fish (Pseudotolithus sp.) and king fish (Scomberomorus tritor), used as traditional condiment to enhance the flavour of many dishes were purchased from processing sites and markets, for physico-chemical and microbiological characterization using standard methods. FATE samples exhibited similar water activity level (0.75-0.77), variable pH values (6.88-7.68), variable amounts of dry matter (43.4-47.2 g/100 g), salt (18.7-26.6 g/100 g DM), protein (49.2-53.8 g/100 g DM), lipid (10.8-47.4 g/100 g DM), thiobarbituric acid reactive substances (24.8 to 27.1 mg malonaldehyde/kg DM), total volatile nitrogen (453.6 to 618.6 mg N/100 g DM) and acidity index (1.7 to 4.9 g oleic acid /100 g DM), various organic acids and histamine contents within acceptable limit of 20 mg/100 g for 87% of samples analysed. For all these chemical components, significant differences (p < 0.05) were observed between fish species and between sampling places. Total viable counts were ranged between 3.6 to 4.2 Log cfu/g. No Salmonella and Listeria monocytogenes were found in any FATE sample. The technological flora such as lactic acid bacteria were enumerated (1.2 Log cfu/g) in 42% of samples while coagulase negative Staphylococci were found in all the FATE samples (2.9-3.9 Log cfu/g).

Quality of Sardine (Sardinella sp.) Peda during Storage as Affected by Salting Pre-Treatment Process and Chitosan

“…Sardine peda crude protein contents were comparable to those of India's fermented fish reported by Roy [26] and Gupta [29], but much lower than that of the Africa's lanhouin (around 50 g/100g DM) [23]. Total lipid content of the sardine peda were lower in comparison to 11-16% lipid content of fermented fish reported by Kindossi [23], Roy [26] and Gupta [29]. During fish fermentation, complex biochemical reactions increase which extensively change the initial attributes of the fish tissue.…”

“…However, TVBN of other sardine peda samples were between 128.75-584.54 mg N/100g, and after 4 months of storage, it was mostly above 300 mg N/100g. This final TVBN range was higher than that of fresh Indian fermented fish telesech published by Roy [26], but lower than that of African fermented fish lanhouin, which had a TVBN of 453.6-618.6 mg N/100g [23]. The high TVBN may result from the long exposure of the fish in open conditions, without salt, which makes them prone to enzymatic and microbial activity and produce higher amounts of low molecular nitrogenous products [26].…”

“…There was no interaction effect between treatments (P0K1, P0K2, P1K1, P1K2, P2K1, and P2K2) and storage time (0, 2, and 4 months) on the moisture, crude protein, and total lipid contents. The peda salt content was lower than those of peda reported by Thoriq [21], hout-kasef and lanhouin, types of fermented fish published by Gassem [22] and Kindossi [23]. However, the peda salt content conformed to that of peda [24] and lanhouin [25].…”

“…Figure 1 illustrates the change in total bacteria, which ranged from 9.8-10.33 log cfu/g at the start of peda storage, increased significantly (P < 0.05) to 11.62-12.47 log cfu/g after 2 months, and increased again to 13.29-14.08 log cfu/g after 4 months. The total bacteria of the sardine peda was higher than those of most reported fermented fish which ranged from 3-9 log cfu/g [23], [26], [29] [30], [31]. These reported low total bacteria amounts were mostly from fresh fermented fish products that had not been stored for a long time.…”

“…The increase in pH during storage was affected by the continuing enzymatic and microbial activity after processing. The pH rose conceivably due to microbial proteolytic activity during fermentation and the storage resulted in the formation of nitrogenous compounds that accumulate in the fermented product [23], [28]. All sardine peda samples with chitosan (K2) had a pH lower than those without chitosan since the beginning and during storage.…”