Novel application of biofortified crops: consumer acceptance of pasta from yellow cassava and leafy vegetables

Abstract

BACKGROUND

Newly developed yellow biofortified cassava has been adjudged as a cost‐effective solution to vitamin A deficiency in low‐ and middle‐income countries with high cassava intake such as Nigeria. In this study, yellow cassava was developed into a novel pasta enriched with amaranth vegetable and tested among consumers. Attitudes, perception, motives for consumption and perceived barriers were ascertained using focus group discussions and randomised face‐to‐face interviews, while liking, preference and ranking of the novel food were established through consumer sensory perception.

RESULTS

Willingness to consume the new food, low food neophobia (32%), a health‐driven consumption pattern, as well as an appreciable acceptance for the developed pasta, was established among the consumers. Ugwu (Telfairia occidentalis) was found to be the most preferred leafy vegetable. The yellow cassava pasta was ranked better than the conventional white cassava.

CONCLUSION

This study shows new avenues to valorise yellow cassava by which nutrition security can be improved in low‐ and middle‐income countries of Africa. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

INTRODUCTION

Micronutrient deficiencies, known as hidden hunger, affect over two billion people worldwide. ¹ In Nigeria, a high intake of white‐fleshed cassava (up to 940 g per adult per day fresh weight) is associated with poor‐quality meals, low dietary diversification and limited consumption of micronutrient‐rich foods such as leafy vegetables. ² , ³ Hidden hunger is prevalent in Nigeria, with the world's largest cassava production. ⁴ Among children under 5 years, the prevalence of iodine deficiency, vitamin A deficiency and iron deficiency anaemia was 29.6%, 29.5% and 28%, respectively. ⁵ , ⁶ Efforts to improve micronutrient intake are still expensive and inaccessible to most people. ⁷ , ⁸ Dietary diversification is especially low among the poor. ⁹ Thus yellow‐fleshed biofortified cassava was introduced in 2011, with a fresh root carotenoid content of 5–11 μg g⁻¹, as a cost‐effective way of improving vitamin A intake. ⁷

The new yellow‐fleshed biofortified cassava varieties (henceforth referred to as yellow cassava) are good sources of pro‐vitamin A carotenoids, but generally low in iron and zinc. Moreover, cassava contains hydrogen cyanide, which requires processing for elimination. The processing significantly causes carotenoid content loss in cassava products, ¹⁰ , ¹¹ from 10–20% in wet paste fufu up to 50–70% in roasted products such as gari, chikwangue and pupuru. ¹² , ¹³ , ¹⁴ Other interventions are thus required to make up for the post‐processing losses and improve the nutritional value of yellow cassava food products. ¹⁵ New foods from micronutrient‐rich leafy vegetables (vitamin A, iron and zinc) and cassava would improve a starch‐based diet's nutrient value. In Nigeria, over 40 different species of affordable leafy vegetables are consumed but in small quantities, ¹⁶ , ¹⁷ , ¹⁸ indicating the potential to reintroduce them in popularly eaten food products.

Traditional food products of yellow cassava were acceptable to Nigerian consumers. ¹⁹ Oparinde et al. ²⁰ studied consumer demand for yellow gari and eba, and consumer willingness to pay (WTP), while Bechoff et al. ²¹ examined acceptability and perception of traditional dough‐like products from cassava (eba and fufu). Other studies were conducted mainly among farmers. ²² These authors reported positive responses to traditional yellow cassava products. Talsma et al. ²³ tested the acceptance of boiled yellow cassava among school children in Kenya and reported likeness for the food and the need for additional food interventions.

To the best of our knowledge, the acceptability of novel food products from yellow cassava has not been studied. In this study, yellow cassava‐based pasta enriched with the leafy vegetable amaranth was developed and tested. Pasta is a worldwide convenience food, which is suitable for adding ingredients rich in bioactive compounds. Pasta is gaining popularity in Nigeria and is eaten as spaghetti, macaroni and instant noodles. Several researchers investigated pasta development as functional food using non‐wheat ingredients and vegetables. ²⁴ , ²⁵ Yellow cassava vegetable enriched pasta is expected to provide consumers with a novel nutritious food that alleviates micronutrient deficiencies. However, consumer acceptance of such foods is pivotal. Bouis ²⁶ also emphasised that acceptability is essential to the development of biofortified crops.

Consumers in low‐ and middle‐income countries are becoming better educated, more demanding and less predictable in terms of purchase behaviour and more conscious about the health aspects of their food. ²⁷ Thus changes in consumer tastes and preferences towards higher convenience food consumption attributed to urbanisation and rising income warrant further study. ²⁸ Consumers can be ‘neophobic’ or ‘neophilic’ regarding taste, implying that neophobic humans have a natural tendency to dislike or even suspect new and unfamiliar foods, whereas neophilic people tend to accept novel foods. ²⁹ , ³⁰ This study evaluated consumer acceptance of new foods from yellow cassava, pasta complemented with amaranth, and determined the main drivers of intended consumption across five states in Nigeria to improve nutrition security for the resource‐poor.

MATERIALS AND METHODS

Sample preparation

The International Institute for Tropical Agriculture in Ibadan, Nigeria, provided yellow cassava variety TMS07/0593, with a carotenoid content of approximately 11 μg g⁻¹ (fresh weight). ⁷ The roots were peeled, washed, grated, de‐watered, pulverised, dried and milled, according to Sanni et al. ³¹ to obtain high‐quality cassava flour. The pasta was prepared by mixing 500 g cassava flour with boiled water in a 1:1 ratio by hand until a solid dough was formed. Pasta enriched with vegetables contained 5 g (w/w) freeze‐dried amaranth powder. A mini extruder (Super Brev, Italy) was used to obtain pasta strands. Pasta samples were prepared according to good hygiene and manufacturing practices. ³²

Study area

This study was conducted between October and November 2019 in five states of Nigeria, representing four of the six geopolitical zones. Two zones were excluded because of pervading insecurity. The locations combined predominantly urban areas such as Lagos and Abuja, and mainly rural areas such as Bayelsa, Enugu and Akure (Ondo).

Study design

The study consisted of focus group discussions and a consumer acceptability study using questionnaires and a sensory perception evaluation among regular consumers of cassava products. The questions targeted (i) differences in acceptability among consumers for yellow cassava products and leafy vegetables, (ii) how demographic characteristics influence acceptability, consumer habits and individual preferences, (iii) the relationship between acceptability and sensorial differences perceived between the pasta samples, and (iv) possible food neophobia to assess potential consumption. There were slightly more males in the study than females, especially in the north, reflecting a society where culture makes men more socially accessible than women. Participants ranged from 18 to 75 years, and were classified as Generation Z, Y, X, or baby boomers (mean age 33.5 years), with Abuja having the highest percentage of Generation Y (21–35 years old) and Lagos the highest number of Generation X respondents. Most of the respondents were single (50%), while the highest percentage of households with children below 5 years was in Bayelsa and Lagos had the lowest. 29% of respondents had higher education, while 15% had a form of post‐secondary education. Bayelsa had a significantly higher percentage of respondents with post‐university education (44%).

Focus group discussions

Three focus group discussions were conducted among 16 consumers: five rural men and women (32–61 years), seven urban women (22–50 years) and four urban men (26–40 years), who were familiar with cassava foods and leafy vegetables to investigate the habits, attitudes and perception of consumers as well as local utilisation of yellow cassava and leafy vegetables. Experienced participants who habitually consume cassava products were selected using local adverts. The focus group discussions helped the collection of data and were incorporated into the general questionnaire. Verbal consent was obtained from all respondents.

Consumer acceptability survey

Data on acceptance of yellow cassava products and leafy vegetables were collected through a consumer survey to assess the effect of various non‐sensory factors (overview in Supporting Information Appendix A). For this study, 1437 people were randomly contacted. Of these, 575 met the requirements and participated in the survey. This purposive sampling indicated an awareness level of about 40% for yellow cassava in the study area. Questionnaires were administered face‐to‐face to the participants by trained university students. Respondents were recruited only if they had consumed yellow cassava and leafy vegetables before.

Questionnaire design

The items in the questionnaire were derived from the focus group discussions. The questionnaire consisted of three sections based on the conceptual framework of the three pillars of food acceptance and its drivers, namely (i) demographic characteristics of the participants using closed questions, (ii) food habits, food neophobia, lifestyle and consumption patterns of the participants rated on 7‐point Likert scale with endpoints (strongly disagree–strongly agree) using an adapted version of the Food Choice Questionnaire, ³³ , ³⁴ and (iii) barriers to consumption, previous eating experiences, familiarity with cassava products and leafy vegetables as well as a willingness to try newly developed cassava pasta.

Sensory perception

In a separate study, overall attractiveness, liking, smell, sweetness, saltiness, flavour, stickiness, firmness, and powderiness of the yellow cassava pasta samples were evaluated by 30 habitual consumers (16 males and 14 females) of cassava products, who were recruited by word of mouth and social media advertisements. The consumers’ age range was 18–45 years. Four cooked cassava pasta samples (coded using three random numbers) were served in different random orders and tested, namely YFP (yellow cassava pasta), YFAP (yellow cassava pasta with amaranth), WFP (white cassava pasta) and WFAP (white cassava pasta with amaranth). The samples were cooked for 20 min, kept warm in a heating device and served using plastic cutlery. First, consumers were instructed and asked to rate the samples’ attractiveness and overall liking (appearance, aroma, taste and texture) on a 9‐point scale (1 = dislike extremely, 9 = like extremely). Next, consumers tasted the same pasta samples and ranked them on intensity (1 = least intense, 4 = most intense).

Statistical analysis

For the focus group discussions, qualitative data were generated on consumers’ attitudes to yellow cassava, leafy vegetables and pasta products. The data guided the construction of questionnaires for the consumer survey. Cleaned data were analysed using SPSS version 25 (SPSS Inc., Chicago, IL, USA). For the eight nominal and ordinal sociodemographic characteristics of consumers, percentages per class were given for each state. Tests on differences between states in these characteristics were done with chi‐square tests. The habits of eating outside the home and food neophobia were described by relative frequencies of six levels on an ordinal scale (‘never’ to ‘always’) and nominal scale (no = 0, yes = 1), respectively. The differences between states, gender, age groups and the frequency of consumption were investigated using a Kruskal–Wallis test with paired comparisons. Consumers’ attitude and motives of choice for choosing their most preferred leafy vegetables were collected using 21 statements to which the respondents answered on a 1–7 Likert scale. Exploratory factor analysis was used to determine the underlying structure of attitudes and motives. For each factor, Cronbach's alpha was used to test for consistency. For sensory perception, Friedman's test and analysis of variance (ANOVA) were used to test for significant sensory attributes differences across the pasta samples judged by consumers.

RESULTS AND DISCUSSION

Focus group discussions

The focus group discussions revealed that participants had positive perceptions about the new yellow cassava–leafy vegetable pasta products and offered suggestions on several other new products that could be acceptable to them, such as snacks and breakfast products. ‘Tapioca’ and ‘Abacha’ (cassava‐based salad) were also frequently mentioned. Several participants expressed willingness to consume the pasta products of yellow cassava and leafy vegetables with a statement such as ‘Yellow cassava pasta is not available in our markets. If it was, I would like to buy.’ In contrast, the unavailability of yellow cassava in the market was generally perceived as a hindrance to consumption. The yellow cassava–vegetable pasta was generally liked among the participants. Participants also expressed a preference for vegetables they were familiar with, while the younger participants claimed ignorance of cooking methods for most of the vegetables mentioned as a reason for non‐consumption (Supporting Information Appendix B).

Demographic characteristics associated with neophobia and consumer attitude across the states

Results showed that most Nigerian consumers are generally neophilic towards new foods (68%). Food neophobia was higher among females (35%) than males (31%), with significant differences across states (P < 0.001). Respondents in Bayelsa had the highest neophobic tendencies, with 42% not willing to try new food. The most food neophilic age group was Generation Z (20 ≤ years), with 57% claiming they like to try new foods. However, baby boomers had higher food neophobic characteristics than other age groups (Fig. 1), in line with studies by Meiselman et al., ³⁵ who established a neophobic tendency among older US consumers and associated older age groups with higher food neophobia. Ullrich et al. ³⁶ also measured ‘food adventurousness’ with a single question: ‘How often do you try unfamiliar foods?’ and reported higher levels for the Z and Y generations. The comparatively higher level of food neophobia found for many elderly Nigerians may affect their acceptance of new cassava pasta food products. Cross‐cultural differences in food neophobia were also observed in all the states, with a relatively higher food neophobia in Bayelsa. Furthermore, a higher education level was related to the willingness to try new food as more educated respondents tended to be more food neophilic. Therefore, less literate individuals seem more likely to reject new foods from yellow cassava and leafy vegetables. Significant differences were also observed across the states in consumers’ frequency of food consumption outside the home (Fig. 2).

Figure 1.

Food neophobia across four Nigerian states by age group.

Figure 2.

Attitude of consumers to eating outside the home across the states in Nigeria.

Cassava and leafy vegetable consumption, habits and attitudes

A high frequency of consumption of yellow cassava and leafy vegetables was observed in all the states, in line with several other reports on Nigerians’ food habits. ³⁷ Most consumers who had already consumed yellow cassava for more than 1 year also ate it with leafy vegetables. Respondents claimed that vegetables are commonly milled, cooked, steamed or stir‐fried and are sparingly eaten but usually not in the raw form. The frequency of cassava and leafy vegetable consumption was significantly different across the states (Table 1), while 82% of consumers habitually consume cassava at least once every week with a form of vegetable. This finding is consistent with focus group discussions, indicating an increased intake of vegetables with starchy staples such as gari, fufu and lafun. As shown in Table 1, most consumers reported eating cassava daily or more than twice a week, with the highest consumption frequency among Bayelsa consumers (67%). The study also showed that consumption frequency was higher for leafy vegetables than cassava, especially in Enugu and Ondo, where about 35% of consumers reported daily intake of leafy vegetables (Supporting Information Appendix G). The self‐reported higher intake frequency for leafy vegetables than cassava among consumers may be attributed to the heightened awareness of the importance of vegetable consumption as advocated by the local authorities and reported in the focus group discussion (Supporting Information Appendix B) – an indication of the positive influence of nutrition education on the acceptance of food by consumers. It is thus expected that increased nutrition education across the country may lead to a higher frequency of consumption. Some studies on commonly consumed leafy vegetables in Nigeria rated Amaranthus spp. as number one. ³⁸ , ³⁹ However, in this study, Telfairia occidentalis (ugwu/fluted pumpkin) was found to be the most preferred leafy vegetable, at 29% consumer preference across the states (Supporting Information Appendix D) and an especially high preference in Lagos, a predominantly urban location, in line with the report of Olatona et al. ¹⁶ , ¹⁷ The most preferred leafy vegetables from this study (fluted pumpkin, amaranth and bitter leaf) were also reported by Adewoyin et al. ⁴⁰

Table 1.

Consumption frequency of yellow cassava and leafy vegetables across the states

	Yellow cassava consumption frequency					Leafy vegetable consumption frequency
	Every day	>Twice/wk	Twice/wk	Once/wk	Once/2wks	Every day	>Twice/wk	Twice/wk	Once wk	Once/2wks
Bayelsa (n)	8	52	12	8	10	26	54	9	4	1
%	8.9	57.8	13.3	8.9	11.1	27.7	57.4	9.6	4.3	1.1
Enugu (n)	0	10	8	7	48	27	33	9	3	2
%	0.0	13.7	11.0	9.6	65.8	36.5	44.6	12.2	4.1	2.7
FCT (n)	11	21	26	17	42	21	43	13	18	13
%	9.4	17.9	22.2	14.5	35.9	19.4	39.8	12.0	16.7	12.0
Lagos (n)	4	15	8	10	47	29	42	16	14	13
%	4.8	17.9	9.5	11.9	56	25.4	36.8	14.0	12.3	11.4
Ondo (n)	13	18	12	24	30	43	36	24	12	8
%	13.4	18.6	12.4	24.7	30.9	35.0	29.3	19.5	9.8	6.5
Total (N)	36	116	66	66	177	146	208	71	51	37
%	8.0	25.0	14.0	14.0	38.0	28.5	40.5	13.8	9.9	7.2

Consumer attitudes and motives for leafy vegetable consumption

Major determinants of consumer attitudes and motives of choice for leafy vegetables were ascertained using exploratory factor analysis (EFA). This analysis revealed the underlying structure of the questionnaire. EFA indicated five factors influencing consumption based on the screen plot of the eigenvalue. These factors explained 52.4% of the variance; the rotations converged in 19 iterations (Supporting Information Appendix K). These results differ from the nine factors presented by Steptoe et al., ³³ as only five factors had items loading 0.50 or more. Our output (Table 2) revealed that Factor 1 was related to the health and nutritional aspects of leafy vegetables. This dimension represented a desire to live and eat healthily. By contrast, Factor 2, familiarity, indicated adherence to established and long‐term habits about food. This segment may tend towards aversion for unfamiliar leafy vegetables. Factor 3 represents the convenience and simplicity of preparation and is equally important to these consumers. Factor 4, sensory appeal, represents how important it is for the consumers to enjoy the food. Factor 5, natural content, is mainly concerned with the naturalness of the food – foods without artificial ingredients. The results show that the main motives of consuming leafy vegetables are related to health, as also reported by other authors. ¹⁷ This result suggests that consumers for whom health considerations are most important will most likely accept yellow cassava with vegetable pasta products.

Table 2.

Motives driving leafy vegetable consumption among consumers

	Loading	Mean	SD	Cronbach's alpha
Factor 1: Health and nutritional aspects				0.87
Has medicinal benefits	0.61	6.33	1.18
Keeps me healthy	0.59	6.35	1.13
High in fibre	0.65	6.06	2.09
Factor 2: Familiarity				0.87
It is commonly eaten by my tribe	0.94	6.30	1.22
It is the food I have been used to	0.88	6.02	1.32
Factor 3: Convenience				0.86
Can be easily purchased	0.55	6.15	1.33
It is easy to wash	0.59
Can be cooked very simply	0.56	6.18	1.44
Factor 4: Sensory appeal				0.87
It is very tasty	0.76	6.10	1.43
Factor 5: Natural content				0.86
It is free from contaminations (e.g. pesticides/fertilisers)	0.78	6.15
It is handled hygienically	0.68	6.02

Consumers’ perception of yellow cassava pasta among participants

The initial perception of consumers for the pasta product was tested by rating their general impression of the product on a 6‐point ordinal scale from (1) ‘very positive’ to (6) ‘negative’. Overall, 71% of the 476 respondents gave a positive/very positive score (Fig. 3), an indication that consumers will likely welcome a cassava pasta product. Over 50% of Abuja and Ondo consumers were very positively inclined towards the yellow cassava product, while Abuja also had the highest percentage (20%) of neutral to negative consumers.

Figure 3.

Perception of consumers towards yellow cassava food product across the states.

Barriers to the consumption of yellow cassava and green leafy vegetables among participants

The most frequently mentioned barriers to the consumption of yellow cassava were ‘Availability’, ‘Taste’, ‘Convenience’ and ‘Health’ (but all less than 10%), while the main perceived barrier to vegetable consumption was ‘Health concerns’. As shown in Fig. 4, the primary barrier to the consumption of yellow cassava observed in this study was availability, but still only at less than 10%. The barrier associated with the availability of yellow cassava was also reported by Talsma et al. ²³ among Kenyan consumers. Results from the consumer survey corroborated the complaint of focus group participants about the scarcity of yellow cassava in the market and the low awareness for yellow cassava observed during participants’ recruitment. The distribution of yellow cassava across Nigeria appears to be low, as confirmed by the responses of consumers. Participants also indicated that the barriers to consuming leafy vegetables were related to taste, familiarity, personal preference, convenience, preparation and health concerns (purging/diarrhoea). Several leafy vegetables with bitter tastes are laborious to prepare, thus reducing their consumption. Moreover, poor preparation techniques of some vegetables were also said to result in health issues. However, the main barrier to consumption was related to health concerns, as some respondents (29%) who had issues with the consumption of leafy vegetables claimed that some vegetables cause diarrhoea. Due to the high fibre content of leafy vegetables, some cruciferous vegetables may cause bloating and gas pains or induce diarrhoea when consumed too frequently. ⁴¹ , ⁴² This barrier to consumption was similarly reported among mid‐Western African American women. ⁴³ Generally, the barriers to vegetable consumption mentioned by Nigerian consumers were also similar to the findings of Lucan et al. ⁴⁴ among African Americans residing in the USA. They reported the main barriers to consumption – taste, cost, health, convenience and availability – whereas Santos et al. ⁴⁵ reported ‘cost ‘and ‘familiarity’ as main barriers to vegetable consumption.

Figure 4.

Perceived barriers to consumption of yellow cassava and leafy vegetables.

Preferred new products from yellow cassava among consumers

Pasta products, such as macaroni, spaghetti and noodles, were mentioned most frequently as a preferred new yellow cassava product by 25% of the respondents, followed by breakfast cereals (20%) (Supporting Information Appendix I). As shown in Fig. 5, pasta products were consumers’ choice across the states, particularly in urban locations, confirming that pasta products are fast gaining acceptance among Nigerian consumers. Other products mentioned by the respondents were ‘Abacha’ (a form of cassava‐based salad) and tapioca or mingau (a cassava‐based pudding). In Bayelsa, many respondents (39%) expressed the desire to have yellow cassava made into porridge, puddings and local beverages.

Figure 5.

Preferred new food products from yellow cassava by consumers across the states.

Sensorial differences among samples

ANOVA of the ranking of test results indicated some significant differences between pasta samples for the evaluated attributes at P < 0.05 (Fig. 6). YFP was ranked significantly higher on attractiveness (P = 0.00) and overall liking (P = 0.00) than the other samples, indicating higher acceptability, while YFAP did not differ significantly from the other samples. A significant difference (P = 0.041) was observed between the samples in terms of stickiness. YFP was ranked as most sticky, while WFAP was ranked least sticky. A significant difference (P = 0.001) between the samples in terms of firmness was also established. The sensory results show that YFP was ranked highest in firmness. No significant differences were found in sweetness, saltiness, flavour intensity and powderiness among the samples.

Figure 6.

Results of sensory perception YFP (Yellow cassava pasta, WFAP (white cassava with amaranth vegetables pasta, YFAP (yellow cassava with amaranth vegetable pasta and WFP (white cassava pasta).

Study limitations

A limitation of this study was the predominant use of student interviewers. However, this high number of students reflects Nigeria's demographic structure, where 50.3% of the population is between the age of 15 and 54 years and the literacy level is at 62%. A high literacy level was observed in this study and may have impacted the low food neophobia observed among the study population, as studies have shown that neophobia is lower among better‐exposed individuals. ³⁵ This study indicated that at present ugwu may have become the most preferred leafy vegetable in Nigeria, contrary to existing literature. Thus further research is needed on the acceptability of a yellow cassava pasta combined with the most preferred leafy vegetable, ugwu.

CONCLUSION

Our study, aimed at ascertaining consumer perception and attitude to consuming a new yellow cassava pasta complemented with a vegetable, confirmed modest acceptance for the novel food product. Generally, consumers eat vegetables more frequently than yellow cassava and preferred ugwu to other leafy vegetables. Interestingly, health considerations were the main driver in consuming yellow cassava foods. In contrast, the most prominent barrier to consumption was availability, as awareness is still low in Nigeria, almost a decade after the introduction of yellow cassava. Efforts at making yellow cassava more accessible to people thus need to be intensified by cassava sector stakeholders across the country. The health benefits of the novel food, used as the key selling point, should be mentioned on package labels and marketing materials to improve the acceptance of cassava–vegetable pasta. Yellow pasta was better accepted than cooked yellow pasta with vegetables, an indication that the sensory quality of the product needs to be improved. To our knowledge, this is the first time a vegetable‐enriched yellow cassava pasta was introduced to the Nigerian population, and acceptability was higher than expected. There is thus a potential to develop more quality nutritional novel food products using yellow cassava, as consumers mentioned several other convenience food products that differ from the well‐known, traditional products. The findings of this study highlight a need to conduct experimental studies on the nutritional composition of the novel pasta products to ascertain the nutritional value after processing and the bioavailability of vitamin A and minerals in the human system.

COMPLIANCE WITH ETHICAL STANDARDS

This study was approved by the Nigerian Ministry of Health Ethics committee (Approval No. NHREC/01/01/2007‐31/3/2020).

AUTHORS’ CONTRIBUTIONS

All authors provided feedback on the manuscript and approved the submitted version.

CONFLICTS OF INTEREST

The authors declare that they have no conflict of interest.

Supporting information

Appendix S1. Supporting Information: Novel application of biofortified crops.