1 Introduction

According to FAO Sheet [1], cassava as part of the main food substrate serve over 200 million people is grown extensively in Nigeria and many other tropical locations. In Nigeria, cassava food items, such as ‘lafun’, ‘fufu’ and ‘garri’ commonly consume in southern part of Nigeria, are vital indigenous foods [2]. It has been reported that cassava are deficient in vitamins, proteins and amino acids, but rich in carbohydrate, which 85% of it contributed to the total body weight [3]. To avoid losses to deterioration from post-harvest and encourage sustainability, it is processed into food items with value additions to improve the palatability, safety and reduce toxicity [4]. One of the final products of cassava is ‘fufu,’ an acid-fermented, which its nutritional and organoleptic qualities are improved through fermentation [3, 4]. It is commonly made in Nigeria and other nations by soaking cassava peeled roots in water to ferment before stirring in hot water to make a dough meal [3]. The fermentation of cassava roots do improve its quality, as different batteries of microorganisms will express their metabolic activities to contribute to its flavour and odour [4]. These, usually make the microbial load to increase with presence of class of Enterobacteriaecea, including pathogenic microbes and reduction in the fermentation process [4, 5]. The use of inoculum or inocula are the new technology to improve the overall quality and nutritional of food acceptability especially for ‘fufu’ production, which will not only prevent unwanted microbiota, but as well speed up the fermentation time and to enhance the quality attributes like nutrition, functional and general acceptability [5,6,7].

Functional properties of food (s) are the vital properties of foods that reflect how the molecular conformations, structural compositions, and physicochemical properties of food interacted [8, 9]. The functional properties of foods also describes how ingredients behave to reflect on the final appearance, texture, and flavour, is another aspect of a food's functional qualities. Viscosity is one of the factors that determine acceptability and show the effect of any treatment on fabricated foods. The ability of food to paste, especially food high in starch can be employed to monitor how satisfactory dough behave when gelatinized or swollen and cooled [10].

Production of objectionable odour in ‘fufu’ has been major contributed factor that has limited its consumption even though people especially from the Eastern part of Nigeria known to be lovers of ‘fufu’ still consume it. In order to reduce the odour of ‘fufu’ and enhance its quality to be more acceptable to larger consumers and at the same time expand its small-scale industrialization, the cassava mash was inoculated with pure starter cultures at varying grouped by enhancing the technology (optimization). Therefore, the purpose of this research aimed at determining microbial, functional, as well as chemical attributes associated with odourless ‘fufu’.

2 Methods and materials

2.1 Gathering of resources

Farmers were given cassava root cultivars created by IITA, Ibadan, with the name TMS 320572 to plant in order to have maturity as early as 9 months with high yield, and lower hydrogen cyanide (HCN). Although they were cultivated all year round, they were uprooted in November when they reached maturity. Teaching and Research Farms of Federal University of Technology Akure, Ondo State, Nigeria, are situated at 7.2960° N, 5.1506° E. Ethanol (95% v/v), Orthophosphoric acid, buffer (pH 7.0), EDTA, potassium phosphate, sodium hydroxide pellets, Microbial agars [Potato Dextrose Agar (PDA), deMan Rogosa Sharpe Agar (MRS), Nutrient Agar (NA)], L-S-Biotech, USA, potassium phosphate (5%), potassium iodide solution (w/v), Ag (NO3)2 solution, and formalin saline (10%). All were obtained from SIGMA-ALDRICH, Germany and were of analytical grade.

2.2 Microbiological examinations

The method of [11] with slight modification was employed. The cassava tubers (TMS 320572) underwent spontaneous fermentation. The isolating media [Potato Dextrose Agar (PDA), deMan Rogosa Sharpe Agar (MRS) and Nutrient Agar (NA)] were made in accordance with the manufacturer's instructions. They were sterilized using an autoclave (Model YX-280A) manufactured by Pathway Medical (England) set at 121 °C for 15 min. The saline solution's dilution factor of 10–3 was used. Sterilized nine milliliters (9 ml) of saline solution were homogenized with one gram (1 g) of each ‘fufu’ sample and was serially diluted until a 10–3 level of dilution was achieved. One milliliter (1 ml) from the last dilution of each sample was dispensed into sterilized plate, was pour-plated over the previously sterilized medium, allow solidifying and inverted. The bacterial growth plates were incubated in both anaerobic jar at 37 °C for 48 h and aerobic at same temperature for 24 h. The fungal growth were incubated at 25 °C for 72–120 h. Each microbial plate was made in threefold.

2.2.1 Identification of microorganisms

The morphology of the microbial colonies were observed on the cultured plates and their biochemical tests were conducted. They were observed with an oil immersion lens (X100) objective lens microscope (Models CHA-213, Tokyo, Japan). The isolated pure microbial analyzed were identified using manual of identification by Bergery's [12]. Conversely, the fungal isolates were identified by low power objective lens microscope (Model CHB-213, Tokyo, Japan), where morphological observations, and cultural characteristics of using dye soaked with cotton-blue lacto phenol solution was used [13].

2.2.2 Standardization of identified microorganisms

The identified microorganisms to be used as inoculum were performed using the McFarland standard as a guide in accordance with Babatuyi et al. [14] protocol. Broth culture (18 h old) of each starter culture was rinsed three times in buffer (0.1 M potassium phosphate) as pH 7.0 and a chilled centrifuge (Model Harrier 18/80, manufactured by Henderson Biomedical LTD MSE, (UK) was used to centrifuge for 10 min at 6000 rpm. A visible single beam spectrophotometer (Model V-721 VIS, manufactured by Shanghai Yoke Instrument Co, China) set at 600 nm wavelength was used to standardize the cells after being aseptically re-washed in 20 mL of the same buffer. This resulted the cells having about 1.5 × 108 in suspension of 1.0.

$$0.{5 }\,McF = { 1}.{5 } \times { 1}0^{8} cells\;to\;be\;equal\;to\;0.0{6 }(OD\;{6}00\;nm)$$
(1)

2.3 Making ‘fufu’ from cassava roots

2.3.1 Production of mash from cassava roots

Sorting, cleaning, peeling, and re-washing of fifty-two kilograms (52 kg) of cassava roots before they were divided into three sections as described by Bababtuyi et al. [14] protocol with slight modification. One of the sections was grated before blanching for 15 min at 65 °C and inocula were added. It was divided into six fractions namely as: Bacteria (BA), Yeast & Bacteria (BY), Yeast (YA), Mould & Bacteria (BM), Yeast & Mould (MY), and Mould (MA). Another set in fraction was grated without inoculum (CW), while the last set in fraction was chopped into 3 to 4 cm length, immersed in 300 mL of sterile water (SW) to make eight samples in all.

2.3.2 ‘Fufu’ preparation

All the fractions of cassava mash have 200 g and 300 mL of sterile water with 30 ml of inocula broth to be added into the fractions separated for fermentation with inoculum. Each inoculum of 18 h old culture was standardized by centrifuging the pure culture in bench-top centrifuged (Model 80–3) manufactured by Labscience, England, by washing in sterilized distilled water at 3000 rpm for 5 min. The supernatant was discarded, while the cell residues were re-washed in sterilized distilled water with the same centrifuge used above to spin three times. The suspension of the serially diluted cells were inoculated into specific culture media for microbial quantification. Sterilized distilled water was used to make up 30 ml of inocula broth for each sample in ratio 1:10 for inoculum fermentation. Each portion was placed in a closed container called fermentor (Model KSS-SSF-004) manufactured by Krishna Scientific, Chennai, India). Following three days of fermentation at 27 ± 2 °C, each, muslin cloth used to get rid of the shafts from the samples. Flowable suspension of each sample was allowed to settle before solidifying and hot-air oven with Model no: (TT-9053) manufactured by Techmel & Techmel, (USA, 2015) was use to dry the samples for three days at 60 °C. It was grinded into powdery form with the use of Kenwood Electronic (Model KM 901D) laboratory blender manufactured by Hertfordshire (UK). During the fermentation period of ‘fufu’ fractions fermented with inocula, their fermenting water were replaced with same equal water and inocula broth for three days straight at every 24 h with the aid of McFarland protocol as described by Babatuyi et al. [14] (Supplementary material 1).

2.4 Analyses of chemical parameters

2.4.1 pH

The pH of an odourless ‘fufu’ fermented with mixed starter cultures carried out with pH meter (model 7020) having electrode made of glass manufactured by Kent Ind. Measurement Ltd as described by A.O.A.C. [15]. The values were carried out in triplicates at every 24 h.

2.4.2 Total titratable acidity (TTA)

The TTA of odourless ‘fufu’ fermented with mixed starter cultures was carried out as described by A.O.A.C. [15] and the Lactic acid was calculated. The values were carried out in triplicates at every 24 h.

$$TTA\, \%=Average\, titre\, value \times 0.1\times 0.009008 \,h \times 100$$
(2)

2.5 Functional compositions

2.5.1 Bulk mass density

The described method of Karim et al. [16] was followed. Twenty grams (20 g) of each samples was measured into measuring cylinder with 50 ml. It was tapped until it was fully packed and the measurement was written down.

$$Bulk\, density\, (g/ml) = \frac{Weight\, of\, the\, sample }{ volume\, of \,the \,sample\, after\, pouring}x 100$$
(3)

2.5.2 Swelling index

The method of Babatuyi et al. [17] was followed with modification as described. The ‘fufu’ flour sample (10 g) was dispensed in measuring cylinder by hitting the cylinder gently for 2 min in order to record the first value and distilled water of 50 ml was added to it. This was left to settle for about 4 h before taking the final record of the volume. The values were carried out in triplicates at every 24 h for calculation.

$${\text{Therefore}},\,\%\, Swelling\, index\, \left( {SI} \right) = \frac{{Final\, volume\,\left( {ml} \right) {-} initial\, volume\, \left( {ml} \right) }}{{Initial \,volume\, \left( {ml} \right)}} \times 100$$
(4)

2.5.3 Absorption capacities (water and oil)

These were carried out using Babatuyi et al. [17] protocol as guide. One (1 g) gram each ‘fufu’ sample was measured into different centrifuge tube and 10 ml of either water or oil was added. Each separated liquid from the sample was discarded and the residue was measured. The weight gain was recorded for either water or oil absorbed.

$$\%\, WAC /OAC = \frac{{Weight\, of\, the\, sample + tube {-} Weight\, of\, sample + tube\, after\, centrifuging}}{ Weight\, of\, the\, sample} \times 100$$
(5)

2.5.4 Cooling viscosity

Determination of the viscosity of the ‘fufu’ was followed using Singh and Kaur [18] protocol. Each ‘Fufu’ sample was prepared as 5% and 2% (w/v) respectively in water bath with controlled temperature (Labo model WBN 007). The samples were boiled for 30 min at 90 °C and continuous stirred without interruption. A soft moist mixture was extracted into rotary viscometer (Model VT-04E) manufactured by Rion Viscotester Co Ltd (Tokyo Japan) to measure the temperature between 30 and 90 °C.

2.5.5 Whiteness

The whiteness of all the ‘fufu’ samples was determined using electric laboratory Kett photometer (Model C 600) manufactured by Green Agritech Equipment (Ambala, India). Fifty grams (50 g) of each sample was poured into the cuvette of the photometer before placing inside it. The percentage value read was observed on the digital display of the equipment.

2.6 Pasting characteristics

Method according to Sanni et al. [19] was used as guide in determining pasting properties of odourless ‘fufu’ with.

Rapid Visco Analyser (RVA) Thermocline for Windows Software (NT 2000 version XP TCW EXE, 2023) manufactured by Perten Instruments (Australia). Five (5) grams of each sample was filled into container with distilled water of 25 mL and the canister was put inside it before the paddle. Its blade was push suddenly but slightly more than ten times vigorously upward and downward till there was smooth flour. To ensure that the paddle was aligned correctly, the paddle was put into the canister and both were tightly pushed into the paddle to couple together. The instrument's motor tower was depressed to start the measurement cycle. The ‘fufu’ samples were subjected to high temperatures and regulated shear, which caused them to gelatinize and increase in viscosity. This demonstrated their stable state. The samples were cooled down to observe if there was setback in the gelatinization process. At temperature of 95 °C, the flowable suspension was heated at a constant time of 3 min to hold before reducing the temperature at 50 °C with the same holding time at 13.25 °C/min. The heating and cooling rates were kept constant.

2.7 Sensory qualities

Sensory qualities of an odourless ‘fufu’ fermented with mixed starter cultures samples were evaluated with 20 semi-trained panelists among the university community that cut across both male and female with Poste et al. [20] 9-point Hedonic scale technique. Each of the ‘fufu’ flour was made into stiff dough with addition of boiling water to stir. A "like extremely" score of nine and a "dislike extremely" score of one were given as the rating scale. The visual (colour), tactile (texture), olfactory (aroma), as well as whole acceptability were the attributes that were examined. Samples coded in 3-digit random number for independent evaluation were given to the assessors.

2.8 Analysis of statistics

The Statistical Package for Social Science (SPSS) version 21.0 (IBM Inc., New York, NY) was used to separate the means of the collected data using New Duncan's Multiple Range Tests (NDMRT), while the Analysis of Variance (ANOVA) was used to calculate the statistics differences. The results are shown as Mean ± SEM (n = 3).

3 Results and discussion

3.1 Population of microorganism loads during ‘fufu’ fermentation

The presence of microorganism loads in ‘fufu’ samples are shown in Fig. 1. There was a gradual rise in both bacteria (Mesophilic aerobic and Lactic acid bacteria) and fungi loads in all the media used throughout the period of fermentation starting with 2.06 × 105 cfu/g, 7.25 × 106 cfu/g and 3.78 × 104 sfu/g respectively. The population of Lactic acid bacteria (LAB) had the highest load (1.93 × 107 cfu/g) contributing to the acidification of the ‘fufu’ within 72 h of fermentation compared to other media used. There was a limited number of microorganisms isolated because of proliferation of LAB cells; similar in line with findings of Chikindas et al. [21]. The LAB usually releases some metabolites during fermentation substrate as a result, made other bacterial growth to be controlled. This could be due to the release of enzyme (amylase) to limit the proliferation of pathogenic and spoilage microorganisms present. The amylase enzymes function to release sugars to secure energy for available microbes in the substrate. Some fungi and bacterial like Corynebacterium spp. function to as odour and flavor enhancer in food [22, 23].

Fig. 1
figure 1

Microbial load of microorganisms on different media used during cassava mash for ‘fufu’ production. NA: All mesophilic aerobic bacteria; MRS: Lactic acid bacteria; and PDA: Yeasts and Moulds

Full size image

Odom et al. [24] and Ewanfo et al. [3] buttressed this point from their work that high acidic level involved in fermented ‘fufu’ could be enough in microbial destruction. Contamination of finished product may arise and may as well alter it. Microbial metabolic, growth and survival rate in foods is response to the environmental stress reaction, which will also determine the food matrix [25]. Spoilage and pathogenic microbes within fermented products are controlled with antimicrobial agents [26].

3.2 Effect of starter cultures of odourless ‘fufu’ samples on its chemical compositions

The chemical compositons present in ‘fufu’ samples produced by using different starter cultures at 72 h fermentation are shown in Fig. 2. The pH ranged between 4.2 and 7.7, while the total titratable acidity ranged between 0.18 and 1.23%. pH is to determine the rate at which a product is fermented and high acidity level in the ‘fufu’ sample may cause low acceptability of the sample. Sample SW had the lowest TTA (0.18%) and the highest pH (7.7). The ‘fufu’ sample SW had the least amount of acidity, which could have been the reason for its good acceptability by all panelists. ‘Fufu’ sample MA had the highest TTA (1.23%) due to highest value ascribed for its loose sugar during lactic acid fermentation. This made it to have definite set of microbial battery in the substrate [27], thereby not acceptable. When the ‘fufu’ samples were compared to the standard for edible cassava flour recommendation by SON [28], which is 1.0 for TTA (%), all the ‘fufu’ samples prepared during this research were acceptable due to the lower amount of TTA values except samples YA, BM and MA (1.02, 1.14 and 1.23%) respectively with higher values than acceptable recommended value for TTA.

Fig. 2
figure 2

Effect of starter cultures on the chemical compositions of the odourless ‘fufu’ samples. BA: Bacteria; BY: Yeasts and Bacteria; YA: Yeasts; BM: Moulds and Bacteria; MY: Yeasts and Moulds; MA: Moulds; CW: Grated without inoculum; SW: Immersed in water without inoculum

Full size image

3.3 Functional properties of the odourless ‘fufu’ samples fermented with starter cultures

The bulk densities (g/ml3) and swelling index of ‘fufu’ samples are shown in Fig. 3a. The bulk density ranged between 0.588 and 0.769 g/ml3. ‘Fufu’ samples BY (0.714 g/ml3), YA (0.769 g/ml3), CW (0.769 g/ml3), MY (0.769 g/ml3) and MA (0.714 g/ml3) were higher compared to samples BA (0.588 g/ml3) and SW (0.588 g/ml3). This increase causes the ability of the ‘fufu’ to disperse in hot water during reconstitution suggesting a good dough, hence economical and takes little quantity to produce more quantity of reduced thickness of paste for quality dough meal [29, 30]. Meanwhile, low bulk density could be due to the unbind nature of the starch polymers. The state at which the dough being able to increase in size characterized the amount of starch compositions (amylopectin and amylose) quantity available in dough, which defines its swelling index. The lesser the rate of associative forces in dough, the more its swelling index. High swelling index observed in the ‘fufu’ samples MY (2.20 ml) and MA (1.30 ml) could be due to the activities of the moulds penetration which could enabled the starch granules to break down in the ‘fufu’ samples and allows it to take more water during reconstitution into dough meal hence, economical [16, 29].

Fig. 3
figure 3

The effect of starter cultures on the functional conmpsitons (a Bulk density & swelling index, b Water & oil absorption capacities, c viscosity at 2% & 5%, and d Whiteness) of 'fufu' samples

Full size image

Figure 3b shows both water (WAC) and oil (OAC) absorption capacity levels in ‘fufu’ samples. ‘Fufu’ sample MY recorded highest WAC (580%) and sample YA had the least (300%) values respectively. It is very crucial for food’s development. An increase in the samples could be because of mycelial biomass of the fungal hyphae, which usually rooted easily into cassava tuber, thereby making the ‘fufu’ sample to take more water during cooking and enhance its swelling power/index [29]. OAC in ‘fufu’ samples as shown in Fig. 3b ranged between 125 and 214%. Sample BA had the highest (214%) OAC in all the ‘fufu’ samples. It was stated that the difference in the hydrocarbon radicals (side chains) property in the oil could attach to on-polar radicals present in the oil sample. This explained the differences in the oil binding capacity in flours; given high oil absorption capacity to enhance flavour and mouth feel in the food products as well as its palatability [31].

The viscosities prepared with 5% and 2% at 90 °C are shown on Fig. 3c. Viscosity of the ‘fufu’ samples increased with concentration. This could be as a result of microbial activities that might have caused the breakdown of the structural cells of the cassava roots. The ‘fufu’ sample YA had the highest viscosity at both concentrations (2.7% and 1.0%). This could be due to the starch granules exposure during the heat of gelatinization. The rheological viscosity of good ‘fufu’ dough is to have a reduced viscosity; therefore, this could have been the reason why ‘fufu’ samples made with BA at 5% (1.35Cp) and 2% (0.3Cp) most acceptable in sensory qualities evaluated among other ‘fufu’ samples prepared with different starter cultures.

Figure 3d shows the whiteness of the ‘fufu’ samples. Addition of starter culture for the fermentation did not affect the whiteness of the ‘fufu’ samples except samples MY (59%) and MA (68.2%) respectively during fermentation. The reduction in the whiteness might be due to the metabolic activity of the microorganisms present in the sample, which would have reacted to the heat during drying. The whiteness observed in ‘fufu’ samples BY (82.1%), YA (82%) and CW (84.6%) were closer to the value of standard cassava flour whiteness (90%) reported by SON [28].

3.4 The effect of starter cultures of odourless ‘fufu’ samples on the pasting characteristics

The result of the pasting characteristics of the ‘fufu’ are shown on Fig 4. The peak viscosity was between 3481 ± 0.6 RVU to 5856 ± 0.6 RVU of the ‘fufu’. Samples BA (5856 ± 0.6 RVU) recorded the highest, while MY (3582 ± 0.6 RVU) the least. Peak viscosity usually refers to binding ability of the water present in the starch and when mix, has the capacity to increase or absorb water when gelatinized which correlates with the end quality [32].

Fig. 4
figure 4

Pasting properties of the ‘fufu’ produced with different starter cultures. BA: Bacteria; BY: Yeasts and Bacteria; YA: Yeasts; BM: Moulds and Bacteria; MY: Yeasts and Moulds; MA: Moulds; CW: Grated without inoculum; SW: Immersed in water without inoculum

Full size image

The temperature of the ‘fufu’ pasting of samples MY had the highest (75.5 °C) and BA with least (71.7 °C) values, while samples CW had the minimum peak time (3.73 min) and MY showed the highest peak time (4.00 min).‘Fufu’ samples BA, BY, YA and CW had lower pasting temperatures (71.70 ± 0.1, 71.80 ± 0.1, 71.85 ± 0.1 and 71.85 ± 0.1 °C) and short peak time (4.33, 4.00, 3.87 and 3.73 min), while their peak viscosities (5856 ± 0.6, 5262 ± 0.6, 5343 ± 0.6 and 5149 ± 0.6 RVU) were high. This could suggest that their preparation time will reduce compare to sample SW with low peak viscosity (3792 ± 0.6 Cp), high peak time (5.07 min) and high temperature (74.30 °C). It is an indicator for minimal temperature and thus, the energy cost needed for food to be cooked. When the temperature is high, gelatinization rate will be faster and high at the same time.

Samples BA had the highest (4444 ± 0.6 RVU) and MA the lowest (2222 ± 0.6 RVU) values for the final viscosity level. The final visocosity level measured in samples YA (3056 ± 0.6 RVU) and BY (3090 ± 0.6 RVU) did not have any difference in them (p ≤ 0.05). The final viscosity evaluates the tendency to form viscid soft-most mixture following increase or decrease in the food cooked, and this measures the rate of resistance in soft-moist mixture while turning. Setback observed in laboratory made ‘fufu’level ranged from 730 to 1687 Cp with samples BA having the highest (1687 ± 0.6RVU) and MA the lowest values. The setback (753 ± 0.6RVU) of ‘fufu’ sample CW was much lower than that of sample SW (1503 ± 0.6RVU). This could indicate that sample CW would be of good quality product with high stability thus, the ‘fufu’ might be more stable after cooling when made into dough [33]. In contrast, the tendency of the ‘fufu’ samples to retrogration ranged from -839 to 2172 RVU with sample MY (− 839 ± 0.6RVU) being the least among other ‘fufu’ samples. The higher the value, the better the stability of the food sample to reach the retrogradation level without falling back after changing into dough form. ‘Fufu’ samples CW, BY, YA and BA were better (2920 ± 0.6, 2172 ± 0.6, 2287 ± 0.6 and 1412 ± 0.6RVU) than sample SW (345 ± 0.6RVU). Samples CW had the least (1476 ± 0.6RVU) and MY with the highest (2861 ± 0.6RVU) values for the trough level, while samples SW and MY had the highest breakdown (3673 ± 0.6RVU) and the least (620 ± 0.6RVU) levels respectively.

3.5 The effect of starter cultures on the sensory qualities of odourless ‘fufu’ samples

The starter cultures alters the sensory quality of ‘fufu’ as shown in Fig. 5. The texture (mouldability, soft but firm, drawability and smoothness) of each of the ‘fufu’ samples was considered acceptable except samples MY (4.80 ± 0.79) and MA (4.00 ± 0.60), which were rated dislike very much. The texture of commercial market sample (RTE) ‘fufu’ sample (7.70 ± 0.60) was not significantly better than that of samples CW (7.50 ± 0.52) and SW (7.20 ± 0.45) respectively and were rated extremely like. The appearance of the ‘fufu’ samples ranged from 3.00 to 7.70 with significant difference in samples MY (3.00 ± 0.35) and MA (3.58 ± 0.60), which were rated extremely dislike. The colour of the ‘fufu’ samples BA (7.20 ± 0.49), CW (7.50 ± 0.50) and SW (7.00 ± 0.39) were not significantly inferior to ready-to-eat market sample RTE (7.65 ± 0.49), as they were all rated very like between 7 to 9 from the hedonic scale. Sample YA (5.20 ± 0.5) were neither like or not and samples MY (3.70 ± 0.30) and MA (3.60 ± 0.27) were rated extremely dislike. These could be attributed to the inocula used, which were dominated by fungi populace [34]. The aroma (odour) of the ‘fufu’ samples fermented with starter cultures were much better ranged from (5.90 ± 0.6 to 7.70 ± 0.56) than sample RTE (1.60 ± 0.34). ‘Fufu’ to the samples fermented with starter cultures did not give objectionable odour, as it was perceived in sample RTE; contributing to the factors preventing ‘fufu’ consumption by some people.

Fig. 5
figure 5

Starter cultures effect on the sensory qualities of the laboratory prepared ‘fufu’ compared with market sample. BA: Bacteria; BY: Yeasts and Bacteria; YA: Yeasts; BM: Moulds and Bacteria; MY: Yeasts and Moulds; MA: Moulds; CW: Grated without inoculum; SW: Immersed in water without inoculum; RTE: Commercial Market Sample

Full size image

Samples BA (7.17 ± 0.54) and CW (7.37 ± 0.53) were rated the overall acceptable rate extremely like, while samples BY (6.50 ± 0.50), SW (6.87 ± 0.51) and BM (6.30 ± 0.49) were not significantly different from each other. There was drastic reduction of the objectionable odour during the laboratory- fermented samples with elimination of battery of fungi population. This could be as a result of replacing the fermenting water with inocula broth at every 24 h. The yeast population flora increased with increase in period of fermentation contributing to the significant objectionable odour of fermented cassava [35, 36].

4 Conclusion

This research work investigated the effects of chemical, functional and sensory qualities from mixed fermented ‘fufu’ with inocula. Findings established that some of the ‘fufu’ samples could be incorporated into daily diets with improved functional and sensely attributes. Samples BA, BY and CW were better than the traditional well-known ‘fufu’ (SW) and could be recommended due to their processing operation units, which enhanced the nutritional benefits of ‘fufu’. However, justification of potentiality of these ‘fufu’ have been assayed using animal model and published.