Cassava Fermentation and Associated Changes in Physicochemical and Functional Properties

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D. Minerals

Softening of the tubers during fermentation leads to leaching out of nutrients. Hence the effect of fermentation on mineral content has been examined.

The mineral content in fufu and gari prepared by different procedures are given in (Table 3)⁴⁷. Conflicting reports have been made regarding changes in calcium content during fufu fermentation. While Oyewole and Odunfa indicated an increase of 13% in Ca at the end of 96 h (Table 13)⁷⁷, Joseph et al. found a reduction in Ca content in fufu sundried for 15 to 30 d.⁷⁸ The mineral composition of Lafun collected from Nigerian markets has been determined (Table 14).³⁸ The calcium content was enhanced while phosphorous content was reduced. Fe and Al showed a noticeable increase, and other minerals were reduced.

Table 12 : Relative Abundance of Volatile Compounds in Fermented Cassava (Absolute Area of Peak)

	Lab fermented with mixed Culture	Natural Nigerian fermented cassava mash	Traditionally processed gari (Nigerian)
Acetaldehyde	33	12	5
Ethanol	96	976	–
Acetone	1	16	3
Diacetyl	4	22	15

Source : Abe and Lindsay.⁷⁶

Table 13 : Protein and Mineral Contents of Cassava Tubers at Different Periods of the Fermentation Process ( Dry weight Basis)

period(h)	caa	mga	ka	fea	pa	Na	Mnb	Znb	Cu (µ/10g)	Protein(%)
0	50	64	66	12	63	71	50	20	93	1.5
12	47	52	64	19	52	63	56	8	85	1.4
24	37	53	41	30	47	63	58	7	78	0.9
36	52	47	37	22	39	51	68	6	73	0.9
48	53	41	26	9	35	50	60	6	73	0.4
60	54	38	24	7	28	49	43	4	88	0.6
72	55	35	22	7	26	47	38	3	88	0.9
84	55	33	19	6	23	30	27	3	86	1.1
96	57	30	19	6	21	23	20	3	87	1.2

^amg/100g
^bµg/g
Adapted from Oyewole and Odunfa.⁷¹

Table 14 : Mineral Status of Lafun, Minor Elements

	% of dry matter			Fraction in ppm of Dry Matter
Food stuff	Ca	Mg		Mn	Fe	Cu	B	Zn	Mo	Al
cassava	0.13	0.04		12	18	8.4	3.3	24	0.9	19
lafun	0.22	0.06		12	66	5.0	9.5	19	1.0	125

Source : Oke³⁸

Ezeala has studied the changes in mineral content during production of fermented cassava meal.⁷⁹ The phosphorous content showed threefold increase; calcium was unchanged; magnesium and potassium were reduced to one fourth the original values, while sodium was reduced by half. Zinc was not affected. The reasons for the reduction might be ascribed to microbial utilization of the minerals and also leaching out.