Role of dewatering and roasting parameters in the quality of handmade gari

Gari is a common cassava precooked dried semolina in sub‐Saharan Africa. Our study investigated the role of process parameters and mash water content on gari quality during traditional roasting stage. The statistical analysis for eight quality criteria revealed that gari quality is highly influenced by the process parameters adopted by the operators. To emphasise the twin impact of roasting parameters and mash water content, different mashes with varying water content were roasted leading to different adjustments of the roasting conditions according to the operators. When the variability of the water content becomes greater, a greater variability in the final quality of the obtained garis was observed between operators (lightness, swelling capacity, starch content, texture and colour). These results suggest that technological improvements to the gari process could be achieved by appropriate management of the roasting and dewatering parameters.

An interdisciplinary and participatory methodology to improve user acceptability of root, tuber and banana varieties

Breeding programmes for root, tuber and banana (RTB) crops have traditionally considered consumer demand for quality characteristics as low priority against other considerations such as yield and disease resistance. This has contributed to low levels of adoption of new varieties and its potential benefits. To address these challenges, an interdisciplinary five‐step methodology was developed to identify demand for quality characteristics among diverse user groups along the food chain. The methodology includes an evidence review, consultations with key informants and rural communities, processing diagnosis with experienced processors and consumer testing in urban and rural areas. Quality characteristics are then prioritised into a Food Product Profile by user group to inform further work of biochemists and breeders in developing improved selection tools. This initiative presents a new basis to understand consumer preferences for RTB crops. The methodology is currently being applied in projects in sub‐Saharan Africa and is applicable globally.

Analysis of consumer-oriented quality characteristics of raw and boiled plantains in Cameroon: implication for breeding

This study aimed at understanding users' demand for raw and boiled plantains in rural and urban areas in West and Littoral regions of Cameroon. Surveys conducted in eight rural localities consisted of key informant interviews, gender-disaggregated focus group discussions, market and individual interviews. Processing and cooking diagnoses were done with restaurant cooks in urban areas, to know the details of plantain processing and boiling and to understand the quality characteristics of raw plantain that give a most-liked boiled plantain. Local favourite landraces, most cultivated landraces in Cameroon (Batard and Big ebanga) and a new CARBAP/CIRAD hybrid (CARBAP K74) were used. The preference for plantain cultivars was both gender and region-dependent. High-quality plantain should be mature, with big fingers and having a dark green peel colour. The fruit length and girth, pulp pH, dry matter content and firmness were found to be relevant postharvest quality characteristics for plantain breeding improvement.

Boiled yam end-user preferences and implications for trait evaluation

This study aimed to establish the quality characteristics of raw and boiled yam by involving stakeholders along the food chain using a methodology that includes a state of knowledge review, focus group discussion and individual interviews, participatory processing diagnosis with processors and consumer testing. Predictive characteristics of yam for producing a high- and low-quality boiled yam were related to morphological or physicochemical characteristics: peeled yam discoloration and mucilage content being negatively appreciated while the ease of peeling, viscous state of cooking water and the ease of breaking yam into pieces positively valued. High-quality boiled yam should be white or yellowish, sticky to the fingers, nonfibrous, easy to chew, crumbly/friable, with a sweet taste and a good smell. The overall liking of boiled yam is greatly penalised by a too dark colour, hard to the touch, no sweet taste and no friability while eating.

Quality attributes of fufu in South-East Nigeria: guide for cassava breeders

Fufu is a popular traditional fermented wet paste food product from cassava. We examined consumer preferences and quality attributes of fufu in Abia and Imo States of South-East Nigeria, with special attention to gender differences, for the purpose of providing guidance to breeders. Data were analysed by the use of descriptive and inferential statistics. Participants for the interview were randomly selected from a list of farmers in the study area. Individual (II) interviews were conducted among eighty participants comprising twenty-six men (32.5%) and fifty-four women (67.5%). Preferences along the food chain from raw roots to final product were also obtained. Major traits influencing gender-specific consumer preferences are related to appearance, texture and smell. Smoothness, not sticky, easy to swallow and drawability of fufu appear to be major traits that drive acceptance by both men and women. Big roots and smooth skin are prioritised for raw material. Some quality characteristics are conditioned largely by variety traits, while others can be modified by adjusting the processing methods. The complexity of producing high-quality fufu makes it imperative to introduce a multidisciplinary approach into breeding programmes.

The East African highland cooking bananas 'Matooke' preferences of farmers and traders: Implications for variety development

'Matooke' is a staple food made from Highland cooking bananas in the Great Lakes region of East Africa. Genetic improvement of these bananas for resistance to pests and diseases has been a priority breeding objective. However, there is insufficient information on fruit quality characteristics that different users prefer, resulting in sub-optimal adoption of new varieties. This study identified matooke characteristics preferred by farmers and traders, using survey data from 123 farmers, 14 focus group discussions and 40 traders. Gender differences were considered. The main characteristics that were found to drive variety preferences were agronomic (big bunch, big fruits) and quality (soft texture, good taste, good aroma, yellow food). There were minimal geographical and gender differences for trait preferences. Quality characteristics need to be defined in terms of physical-chemical underpinnings so that breeding programmes can apply accurate high-throughput systems, thereby improving adoption and impact of new banana varieties.

Deciphering urban consumer requirements for rice quality gives insights for driving the future acceptability of local rice in Africa: Case study in the city of Saint-Louis in senegal

Rice is the staple cereal in Senegal. Despite the many policies implemented over the last decade, Senegalese consumers still prefer imported over local rice. To understand this preference, this study compares consumer acceptability of three local rice samples versus two imported rice samples. Two focus groups and a consumer test with 120 women were carried out in the city of Saint-Louis in Senegal. The results concerning consumption habits showed that about 85% of the surveyed women consume rice at least once a day (at lunch). The hedonic test showed that consumers appreciated all five rice samples, but the most liked samples were obtained from industrial processing of either local or imported whole and fragrant rice. The least liked sample was a local semi-industrial rice, including 50% broken grains. The results of the just-about-right (JAR) test and check-all-that-apply (CATA) test showed that the sensory descriptors such as white color, well-cooked, and homogeneous grain size had an influence on the consumers' choice of rice samples. However, the most important selection criteria were the homogeneous size of the rice grains, the absence of impurities, both of which are directly linked to the milling conditions, and fragrance, which is related to the variety. The origin of the rice samples did not influence the consumers' choice. This study showed that local rice can compete with imported rice if processing is improved in some small-scale rice mills.

Development of a food product profile for boiled and steamed sweetpotato in Uganda for effective breeding

This study sought to understand user preferences of raw, boiled and steamed sweetpotato, a staple food in Uganda. A sequential methodology involving state of knowledge review, gendered food mapping, processing diagnosis and consumer testing was used in Lira and Kamwenge districts. Preferred raw sweetpotato characteristics were large roots (≥ 3 cm diameter) with a sweet taste, smooth skin and hard texture, while mealiness, sweet taste and good sweetpotato smell were important attributes for boiled sweetpotato. Processors, mostly women, highlighted ease of peeling and sappiness of raw roots. There were gender differences in quality characteristic preferences and perceived importance. The released variety, NASPOT 8, had the highest overall liking in Kamwenge and was well liked in Lira. Penalty analysis of consumer data showed that sweetness and firmness were key drivers of overall liking. The results will support breeding programmes in meeting specific end-user product profiles, selection criteria and uptake of new varieties.

From cassava to gari: mapping of quality characteristics and end-user preferences in Cameroon and Nigeria

User's preferences of cassava and cassava products along the value chain are supported by specific root quality characteristics that can be linked to root traits. Therefore, providing an evidence base of user preferred characteristics along the value chain can help in the functional choice of cassava varieties. In this respect, the present paper presents the results from focus group discussions and individual interviews on user preferred quality characteristics of raw cassava roots and the derived product, gari, - one of the major cassava products in Sub-Saharan Africa - in major production and consumption areas of Cameroon and Nigeria. Choice of cassava varieties for farming is mainly determined by the multiple end uses of the roots, their agricultural yield and the processing determinants of roots that support their major high-quality characteristics: size, density, low water content, maturity, colour and safety. Processing of cassava roots into gari goes through different technological variants leading to a gari whose high-quality characteristics are dryness, colour, shiny/attractive appearance, uniform granules and taste. Eba, the major consumption form of gari in Cameroon and Nigeria, is mainly characterised by its textural properties: smoothness, firmness, stickiness, elasticity and mouldability. Recommendations are made, suggesting that breeding will have to start evaluating cassava clones for brightness/shininess, as well as textural properties such as mouldability and elasticity of cassava food products, for the purpose of supporting decision-making by breeders and the development of high-throughput selection methods of cassava varieties. Women are identified as important beneficiaries of such initiatives giving their disadvantaged position and their prominent role in cassava processing and marketing of gari.

Sensory and physicochemical profiling of traditional and enriched gari in Benin

Gari is a roasted fermented granular product made from cassava in many African countries. It is consumed raw, or added with water, or cooked into a paste. Up to now, gari enriched with palm oil and/or soybean is not available on Beninese markets. To our knowledge, no sensory profiling using appropriate methodology has been conducted on gari in Benin. The sensory studies on gari in Benin and other African countries only included general descriptors (appearance, taste, odor). The aim of our study was to establish a detailed sensory and physicochemical profile of nine traditional and three enriched gari made using different processes in Benin. Fifteen sensory descriptors of raw gari, and gari added with water, were generated and scored using quantitative descriptive analysis. The enriched gari differed from traditional gari mainly in color and odor, while their swelling capacity, texture during chewing, and light sour taste were similar. Marked variability in particle size, particle heterogeneity, water absorption, and sour taste was found among traditional gari. The physicochemical characteristics, such as degree of starch gelatinization, L-lactic acid, and β-carotene contents, were highly variable among the 12 gari. Multifactor analysis revealed highly significant correlations between some physicochemical and sensory properties. The addition of soybean and/or palm oil did not affect most of the sensory properties of the traditional gari. The acceptability of these enriched gari with higher nutritive value by Beninese consumers should be tested to develop marketing strategies.

Cassava traits and end-user preference: Relating traits to consumer liking, sensory perception, and genetics

Breeding efforts have focused on improving agronomic traits of the cassava plant however little research has been done to enhance the crop palatability. This review investigates the links between cassava traits and end-user preference in relation with sensory characteristics. The main trait is starch and its composition related to the textural properties of the food. Pectin degradation during cooking resulted in increased mealiness. Nutritional components such as carotenoids made the cassava yellow but also altered sweetness and softness; however, yellow cassava was more appreciated by consumers than traditional (white) varieties. Components formed during processing such as organic acids gave fermented cassava products an acidic taste that was appreciated but the fermented smell was not always liked. Anti-nutritional compounds such as cyanogenic glucosides were mostly related to bitter taste. Post-harvest Physiological Deterioration (PPD) affected the overall sensory characteristics and acceptability. Genes responsible for some of these traits were also investigated. Diversity in cassava food products can provide a challenge to identifying acceptance criteria. Socio-economic factors such as gender may also be critical. This review leads to questions in relation to the adaptation of cassava breeding to meet consumer needs and preference in order to maximize income, health and food security.

Sensory evaluation and consumer acceptability of a beverage made from malted and fermented cereal: case of gowe from Benin

Sensory profile of gowe beverage was established with 10 gowe samples by 22 semitrained panelists. Besides, consumer study was performed on four representative gowe samples with 141 African ordinary consumers using a modified quantitative descriptive analysis. Gowe samples significantly differed (P < 0.05) with respect to all the sensory attributes, except for cereal odor and cereal taste (P > 0.05). The principal component analysis plot revealed the effects of raw material and process: Sorghum gowe was differently scored from maize gowe samples (P < 0.05). Gowe types from saccharification step (SSaF, SSaSF) evidenced higher scores with respect to fermented odor (41.7) and acidic taste (47.9), while those without saccharification had lower scores of fermented odor and acidic taste, with values of 18.4 and 16.9, respectively. No significant difference was evidenced with respect to the addition of “non malted flour” before or after saccharification. Regarding consumer testing, three distinct patterns of consumer acceptability were observed, which were grouped as “Sugary gowe likers” (63.1% of consumers) followed by “Sugary and saccharified sorghum gowe likers” (20.6%) and “Pure maize gowe dislikers” (16.3%). Irrespective of the consumers cluster, saccharified malted sorghum gowe without sugar was the unique sample scored more than 6 over 9.

Relationships between anthocyanins and other compounds and sensory acceptability of Hibiscus drinks

Chemical composition of Hibiscus drinks (Koor and Vimto varieties, commercial and traditional, infusions and syrups) (n=8) was related to sensory evaluation and acceptance. Significant correlations between chemical composition and sensory perception of drinks were found (i.e. anthocyanin content and Hibiscus taste) (p<0.05). Consumers (n=160) evaluated drink acceptability on a 9-point verbal hedonic scale. Three classes of behaviour were identified: (a) those who preferred syrup (43% of consumers); (b) those who preferred infusion (36%); and (c) those who preferred all of the samples (21%). Acceptability of 'syrup likers' was positively correlated to sweet taste, reducing sugar content and inversely correlated to acidic taste and titratable acidity (p<0.10). Acceptability of 'infusion likers' was positively correlated to the taste of Hibiscus drink and anthocyanin content. The study showed that the distinctions between the acceptability groups are very clear with respect to the chemical composition and rating of sensory attributes.

Variability of grain quality in sorghum: association with polymorphism in Sh2, Bt2, SssI, Ae1, Wx and O2

To ensure food security in Africa and Asia, developing sorghum varieties with grain quality that matches consumer demand is a major breeding objective that requires a better understanding of the genetic control of grain quality traits. The objective of this targeted association study was to assess whether the polymorphism detected in six genes involved in synthesis pathways of starch (Sh2, Bt2, SssI, Ae1, and Wx) or grain storage proteins (O2) could explain the phenotypic variability of six grain quality traits [amylose content (AM), protein content (PR), lipid content (LI), hardness (HD), endosperm texture (ET), peak gelatinization temperature (PGT)], two yield component traits [thousand grain weight (TGW) and number of grains per panicle (NBG)], and yield itself (YLD). We used a core collection of 195 accessions which had been previously phenotyped and for which polymorphic sites had been identified in sequenced segments of the six genes. The associations between gene polymorphism and phenotypic traits were analyzed with Tassel. The percentages of admixture of each accession, estimated using 60 RFLP probes, were used as cofactors in the analyses, decreasing the proportion of false-positive tests (70%) due to population structure. The significant associations observed matched generally well the role of the enzymes encoded by the genes known to determine starch amount or type. Sh2, Bt2, Ae1, and Wx were associated with TGW. SssI and Ae1 were associated with PGT, a trait influenced by amylopectin amount. Sh2 was associated with AM while Wx was not, possibly because of the absence of waxy accessions in our collection. O2 and Wx were associated with HD and ET. No association was found between O2 and PR. These results were consistent with QTL or association data in sorghum and in orthologous zones of maize. This study represents the first targeted association mapping study for grain quality in sorghum and paves the way for marker-aided selection.

Development of NIRS equations for food grain quality traits through exploitation of a core collection of cultivated sorghum

A sorghum core collection representing a wide range of genetic diversity and used in the framework of a sorghum breeding and genetics program was evaluated by near-infrared reflectance spectroscopy (NIRS) to predict food grain quality traits: amylose content (AM), protein content (PR), lipid content (LI), endosperm texture (ET), and hardness (HD). A total of 278 sorghum samples were scanned as whole and ground grain to develop calibration equations. Laboratory analyses were performed on NIRS sample subsets that preserved the core collection racial distribution. Principal component analysis performed on NIRS spectra evidenced a level of structure following known sorghum races, which underlined the importance of using a wide range of genetic diversity. Performances of calibration equations were evaluated by the coefficient of determination, bias, standard error of laboratory (SEL), and ratio of performance deviation (RPD). Ground grain spectra gave better calibration equations than whole grain. PR equation (RPD of 5.7) can be used for quality control. ET, LI, and HD equations (RPD of 2.9, 2.6, and 2.6, respectively) can be used for screening steps. Even with a small SEL in whole sample analysis, a RPD of 1.8 for AM confirmed that this variable is not easy to predict with NIRS.

[Effect of cooking on protein digestibility of sorghum (Sorghum bicolor (L.) Moench)]

The changes in protein digestibility that occur during cooking have interested many scientists. In this study the effect of cooking sorghum in water on the in vitro protein digestibility (IVPD) was evaluated using sorghum grains not containing tannin (SST), and grains containing detoxified tannin (SPD). The results were compared with rice and maize. The effect of sulfites present in the water used for cooking was also determined. The IVPD of sorghum excent of tannins before cooking was 71.1% smaller (p < 0.05) than that obtained for com (80.8%), polished rice (90.6%) or sorgum with detoxified tannins (80.4%). After cooking in water the IVPD decreased to 23.1%, 66.3%, 3.1% and 3.2% for SST, SPD, polished rice and corn endosperms, respectively. The IVPD of SST and SPD treated with 0.1M sodium bisulfite was 65.2 and 50.1%, which corresponds to a decrease in IVPD of 8.0 and 37.7%, respectively. Similar results were obtained when 0.1M sodium metabisulfite is added to the cooking media. These findings demonstrate that sulfites inhibit the sudden decrease of the IVPD of cooked sorghum grains, and suggest that these compounds may block the formation of disulfide bridges (-S-S-) among the gamma-kafirins molecules located on the surface of the sorghum protein bodies or possibly other factors involved which will be later studied.

Tannin elimination and improvement of the digestibility of protein sorghum grains

Three hybrids of sorghum grains [Sorghum bicolor (L) Moench] containing 3.8, 3.0 and 0.2% of tannins were treated. Abrasive dehulling and storage of moist grains were tested separately and in combination to reduce the tannin content and to improve the nutritional quality of grains. The moisture content of the grains was increased from 12 to 30% by humidifying them with water, acetic acid, sodium bicarbonate or sodium hypochlorite solutions. Abrasive dehulling of the grains to a yield between 75 and 80%, humidifying the grains with acetic acid (1% v/v) and storing them during 7 days at 20 degrees C proved to be the most effective procedure. In this way tannin can be totally reduced and the in vitro digestibility of protein can be increased to 87.5%.