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.

BACKGROUND: Boiled yam key quality attributes typical for West African consumers are: crumbly, easy to break, and sweet taste. New yam varieties are being developed but high or medium throughput tools to assess the required quality traits and their range of acceptance are limited. This study assessed the acceptance thresholds of these quality attributes and established the predictive models for screening yam varieties that meet the required consumers' preferences. RESULTS:Overall liking was associated with sweet taste, crumbly and easy to break (r values 0.502, 0.291 and -0.087, respectively). These parameters and selected biophysical parameters highly discriminated the boiled yam varieties. Crumbly texture and easy to break were wellpredicted by penetration force and dry matter, whereas sweet taste by dry matter and sugar intensity. A high crumbliness and sweet taste are preferred (sensory scores above 6.19 and 6.22 for crumbly and sweet taste, respectively, on a 10 cm unstructured line scale), while a too high easiness to break is disliked (sensory scores ranging from 4.72 to 7.62). Desirable biophysical targets were between 5.1 and 7.1 N for penetration force, dry matter around 39% and sugar intensity below 3.62 g/100g. Some improved varieties fulfilled the acceptable thresholds, and the screening was improved through the deviation from optimum. CONCLUSION:The acceptance thresholds and the deviation from optimum for boiled yam assessed through the instrumental measurements are promising tools for yam breeders.

P.butyracea butter, produced by different traditional methods, is often stored for further use in different types of packaging which may affect its quality. The present work aims to evaluate the effect of the production method and the type of packaging used on the physicochemical and microbiological quality of butter during storage. The extraction of Pentadesma butter was first carried out through production monitoring in three repetitions by three different butter producers according to the two most used traditional production methods. Then, butter from production was stored for three months in four types of packaging (aluminium bowls, calabashes, baskets, and black polyethylene bags) in the production environment. The microbiological and physicochemical quality of the stored butter was assessed at 0, 30, 60, and 90 days using normative reference methods. The production method and the type of packaging used had a significant effect on the variation of free fatty acid content (1.54 ± 0.07%–2.6 ± 0.2%), peroxide value (0.96 ± 0.09°meq·O2/Kg–3.9 ± 0.7°meq·O2/Kg), and colour of the butter during storage. In contrast, only the type of packaging material influenced the microbiological characteristics of the butter during storage. After three months of storage, the yeast and mould load was out of the standard range in all packages, i.e., 2.53 ± 0.4 log°CFU/g, 2.9 ± 0.2 log°CFU/g, 4.67 ± 0.2 log°CFU/g, and 1.4 ± 0.2 log°CFU/g for aluminium bowls, calabashes, baskets, and black polyethylene bags, respectively. The aerobic mesophilic germ load was within the standard in black polyethylene bags (3.22 ± 0.08 log°CFU/g), in contrast to the other packages (4.23 ± 0.08 log°CFU/g–6.45 ± 0.13 log°CFU/g). This shows that black polyethylene bags are the best packaging to guarantee the quality of butter. It is important to continue this investigation by storing butter for a longer period of time with more appropriate packaging.

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BackgroundStretchability is the most important sensory textural attribute considered by consumers of pounded yam. It is important both for the processor during pounding and for the consumer during consumption to measure this attribute while screening large populations of yam genotypes intended for advanced breeding and eventual adoption. Texture determined by sensory evaluation and consumer perception is time consuming and expensive. It can be instrumentally mimicked by texture analyzer, thereby providing an efficient alternative screening tool.ResultsTwo instrumental methods (uniaxial extensibility and lubricated squeezing flow) were applied to assess the extensional properties of pounded yam. In order to evaluate the accuracy, repeatability and discrimination of the methods, six yam genotypes with contrasting extensional properties, previously evaluated by 13 panellists in terms of stretchability and moldability and by 99 participants randomly selected in terms of overall liking, were used. Both methods allowed the discrimination of different genotypes as a function of extensional properties. Principal components showed that the genotypes were grouped within separate components associated with specific sensory attributes and their related instrumental texture parameters. Moreover, significant correlations were found between uniaxial extensibility textural attributes, bi‐extensional viscosity and consumer overall liking. However, the sensory attributes were not significantly correlated with instrumental data and consumer overall liking.ConclusionBi‐extensional viscosity and uniaxial extensibility attributes can be used to discriminate and screen yam genotypes for their stretchability characteristics. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.