Sensory guided selection criteria for breeding consumer-preferred sweetpotatos in Uganda

Authors: NAKITTO, MARIAM - International Potato Center; Johanningsmeier, Suzanne; MOYO, MUKANI - International Potato Centre; BUGUAD, CHRISTOPHE - University Of Montpellier; DE KOCK, HENRIETTE - University Of Pretoria; KHAKHASA, ELIZABETH - National Agricultural Research Laboratories; FORESTIER-CHIRON, NELLY - University Of Montpellier; DAHDOUH, LAYAL - University Of Montpellier; RICCI, JULIEN - University Of Montpellier; MESTRES, CHRISTIAN - University Of Montpellier; MUZHINGI, TAWANDA - International Potato Centre

Submitted to: Food Quality and Preference
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/13/2022
Publication Date: 5/17/2022
Citation: Nakitto, M., Johanningsmeier, S.D., Moyo, M., Buguad, C., De Kock, H., Khakhasa, E., Forestier-Chiron, N., Dahdouh, L., Ricci, J., Mestres, C., Muzhingi, T. 2022. Sensory guided selection criteria for breeding consumer-preferred sweetpotatos in Uganda. Food Quality and Preference. 101:104628. https://doi.org/10.1016/j.foodqual.2022.104628.
DOI: https://doi.org/10.1016/j.foodqual.2022.104628

Interpretive Summary: Sweetpotato is a globally important crop that is growing in demand due to its nutritional properties. The introduction of more orange-fleshed varieties in sub-Saharan Africa could alleviate vitamin A deficiency if there is widespread adoption of these varieties. Sweetpotato eating quality plays a vital role in the acceptance of new varieties by consumers. In this study, we developed a standardized language for describing the eating quality traits of cooked sweetpotatoes. It includes 27 clearly defined sensory terms that were used to characterize and distinguish sweetpotato genotypes from an advanced breeding trial. Samples were also evaluated by laboratory methods for texture properties that influence consumer acceptability of cooked sweetpotato, and a range of values was established for screening larger breeding populations for consumer-preferred textures. This combined sensory and instrumental approach facilitates efficient screening of genotypes in sweetpotato breeding programs to increase adoption rates of novel varieties.

Technical Abstract: Prioritizing sensory attributes and consumer evaluation early in breeding trials to screen for end-user preferred traits could improve adoption rates of released genotypes. In this study, a lexicon and protocol for descriptive sensory analysis (DSA) was established for sweetpotato and used to validate an instrumental texture method for which critical values for consumer preference were set. The study comprised several phases: lexicon development during a 4-day workshop; 3-day intensive panel training; follow-up virtual training, evaluation of 12 advanced genotypes and 101 additional samples from two trials in 2021 by DSA and instrumental texture analysis using TPA double compression; and DSA, instrumental texture analysis and consumer acceptability tests on 7 genotypes in on-farm trials. The established sweetpotato lexicon comprising 27 sensory attributes enabled characterization and differentiation of genotypes by sensory profiles. Significant correlation was found between sensory firmness by hand and mouth with TPA peak positive force (r = 0.695 and r = 0.648, respectively) and positive area (r = 0.748, r = 0.715, respectively). D20, NAROSPOT 1, NASPOT 8, and Umbrella were the most liked genotypes in on-farm trials (overall liking = 7). An average peak positive force of 3700 gf was proposed as a minimum texture value for screening sweetpotato genotypes, since it corresponded with at least 46% of consumers perceiving sweetpotatoes as just-about-right in firmness and a minimum overall liking of 6 on average. Combining DSA with instrumental texture analysis facilitates efficient screening of genotypes in sweetpotato breeding programs.