Use of sensory and physico-chemical parameters to understand consumer perception of attiéké, a fermented cassava product.

BACKGROUND: Cassava breeding research programs focused initially on agronomic performance but in recent years they have considered the processability and the organoleptic properties of the final product, to increase the adoption of new varieties. One important cassava foodstuff is attiéké, a fermented and granular product, so it is necessary to determine criteria used by attiéké processors to select raw cassava and the characteristics leading consumers to like this product. This study assessed the attiéké production process, the criteria associated with the quality of attiéké, the sensory drivers of consumer acceptance, and their thresholds. RESULTS: The total processing yield of attiéké varied according to the cassava variety and depended primarily on the fermentation-pressing yield. However, it was not correlated either with the peeling yield or with morphological characteristics of cassava roots. The production of a ton of attiéké required about 150 h. Dry matter, organic acids, soluble sugars, total pectin, and the pH of raw material and attiéké varied depending on the cassava variety. Ten discriminating sensory attributes of attiéké were identified. Consumer testing showed that overall liking for attiéké was associated with sourness, texture, and brightness. Acceptable sensory score thresholds were 1.67-2.18 for sour odor, 4.75 to 6.3 for cohesiveness, and 5.4 to 6.3 for 'mouthfeel sensation'. Attiéké dry matter correlated positively with cohesiveness and moldability. CONCLUSIONS: Several potential solutions are discussed to improve the adoption of cassava varieties for attiéké production. However, further studies need to be carried out to translate the sensory thresholds of texture attributes into robust instrumental methods because texture is an important attribute of attiéké in addition to sourness. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Relation between quantitative descriptive analysis and textural analysis of boiled plantain.

BACKGROUND: Inadequate consideration of textural quality in conventional breeding pipelines of plantains (from breeders to end-users) results in limited impact. Knowledge of the textural quality characteristics of boiled plantain, as preferred by end-users, could help improve the adoption of new clones when these traits are selected for breeding. The present study aimed to evaluate the relationship between instrumental and sensory texture attributes of boiled plantain genotypes. Consumer testing (Just About Right and Check All That Apply tests), sensory quantitative descriptive analysis (QDA), instrumental texture profile analysis (TPA) and penetrometry were conducted with nine accessions: three landraces and six plantain-like bred hybrids. RESULTS: Landraces were considered just-about-right by more than 45% of people for all the sensory attributes (humidity, sweetness, color and firmness), described by characteristics such as smooth on sight, attractive, mealy, firm, plantain taste and yellow. Color and firmness were the most highly scored attributes by panelists for the landraces. Penetrometry discriminated among genotypes better than TPA. Hardness, gumminess, resilience and chewiness were the most discriminatory attributes for TPA, whereas hardness and area under the curve were the most discriminatory attributes for penetrometry. No correlation was found between penetrometry and sensory texture of boiled plantain. For TPA, negative correlations were found between sensory humidity and hardness, as well as between sensory firmness and resilience, whereas a positive correlation was found between resilience and sensory humidity. CONCLUSION: Combining QDA and texture measurements can make the selection of plantain hybrids more effective and improve the adoption of new varieties. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Combined use of sensory methods for the selection of root, tuber and banana varieties acceptable to end-users.

BACKGROUND: The assessment of user acceptability in relation to crop quality traits should be a full part of breeding selection programs. Our methodology is based on a combination of sensory approaches aiming to evaluate the sensory characteristics and user acceptability of root, tuber and banana (RTB) varieties. RESULTS: The four-stepped approach links sensory characteristics to physicochemical properties and end-user acceptance. It starts with the development of key quality traits using qualitative approaches (surveys and ranking) and it applies a range of sensory tests such as Quantitative Descriptive Analysis with a trained panel, Check-All-That-apply, nine-point hedonic scale and Just-About-Right with consumers. Results obtained on the same samples from the consumer acceptance, sensory testing and physicochemical testing are combined to explore correlations and develop acceptability thresholds. CONCLUSION: A combined qualitative and quantitative approach involving different sensory techniques is necessary to capture sensory acceptance of products from new RTB clones. Some sensory traits can be correlated with physicochemical characteristics and could be evaluated using laboratory instruments (e.g. texture). Other traits (e.g. aroma and mealiness) are more difficult to predict, and the use of a sensory panel is still necessary. For these latter traits, more advanced physicochemical methods that could accelerate the breeding selection through high throughput phenotyping are still to be developed. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Multi-block classification of chocolate and cocoa samples into sensory poles.

The present study aims at developing an analytical methodology which allows correlating sensory poles of chocolate to their chemical characteristics and, eventually, to those of the cocoa beans used for its preparation. Trained panelists investigated several samples of chocolate, and they divided them into four sensorial poles (characterized by 36 different descriptors) attributable to chocolate flavor. The same samples were analyzed by six different techniques: Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS), Solid Phase Micro Extraction-Gas Chromatography-Mass Spectroscopy (SPME-GC-MS), High-Performance Liquid Chromatography (HPLC) (for the quantification of eight organic acids), Ultra High Performance Liquid Chromatography coupled to triple-quadrupole Mass Spectrometry (UHPLC-QqQ-MS) for polyphenol quantification, 3D front face fluorescence Spectroscopy and Near Infrared Spectroscopy (NIRS). A multi-block classification approach (Sequential and Orthogonalized-Partial Least Squares - SO-PLS) has been used, in order to exploit the chemical information to predict the sensorial poles of samples. Among thirty-one test samples, only two were misclassified.

Key Aroma Compounds of Dark Chocolates Differing in Organoleptic Properties: A GC-O Comparative Study.

Dark chocolate samples were previously classified into four sensory categories. The classification was modelled based on volatile compounds analyzed by direct introduction mass spectrometry of the chocolates' headspace. The purpose of the study was to identify the most discriminant odor-active compounds that should characterize the four sensory categories. To address the problem, a gas chromatography-olfactometry (GC-O) study was conducted by 12 assessors using a comparative detection frequency analysis (cDFA) approach on 12 exemplary samples. A nasal impact frequency (NIF) difference threshold combined with a statistical approach (Khi² test on k proportions) revealed 38 discriminative key odorants able to differentiate the samples and to characterize the sensory categories. A heatmap emphasized the 19 most discriminant key odorants, among which heterocyclic molecules (furanones, pyranones, lactones, one pyrrole, and one pyrazine) played a prominent role with secondary alcohols, acids, and esters. The initial sensory classes were retrieved using the discriminant key volatiles in a correspondence analysis (CA) and a hierarchical cluster analysis (HCA). Among the 38 discriminant key odorants, although previously identified in cocoa products, 21 were formally described for the first time as key aroma compounds of dark chocolate. Moreover, 13 key odorants were described for the first time in a cocoa product.

Volatile compounds profiling by using proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS). The case study of dark chocolates organoleptic differences.

Direct-injection mass spectrometry (DIMS) techniques have evolved into powerful methods to analyse volatile organic compounds (VOCs) without the need of chromatographic separation. Combined to chemometrics, they have been used in many domains to solve sample categorization issues based on volatilome determination. In this paper, different DIMS methods that have largely outperformed conventional electronic noses (e-noses) in classification tasks are briefly reviewed, with an emphasis on food-related applications. A particular attention is paid to proton transfer reaction mass spectrometry (PTR-MS), and many results obtained using the powerful PTR-time of flight-MS (PTR-ToF-MS) instrument are reviewed. Data analysis and feature selection issues are also summarized and discussed. As a case study, a challenging problem of classification of dark chocolates that has been previously assessed by sensory evaluation in four distinct categories is presented. The VOC profiles of a set of 206 chocolate samples classified in the four sensory categories were analysed by PTR-ToF-MS. A supervised multivariate data analysis based on partial least squares regression-discriminant analysis allowed the construction of a classification model that showed excellent prediction capability: 97% of a test set of 62 samples were correctly predicted in the sensory categories. Tentative identification of ions aided characterisation of chocolate classes. Variable selection using dedicated methods pinpointed some volatile compounds important for the discrimination of the chocolates. Among them, the CovSel method was used for the first time on PTR-MS data resulting in a selection of 10 features that allowed a good prediction to be achieved. Finally, challenges and future needs in the field are discussed.

Insecticidal Activity of the Leaf Essential Oil of Peperomia borbonensis Miq. (Piperaceae) and Its Major Components against the Melon Fly Bactrocera cucurbitae (Diptera: Tephritidae).

The essential oil from the leaves of Peperomia borbonensis from Réunion Island was obtained by hydrodistillation and characterized using GC-FID, GC/MS and NMR. The main components were myristicin (39.5%) and elemicin (26.6%). The essential oil (EO) of Peperomia borbonensis and its major compounds (myristicin and elemicin), pure or in a mixture, were evaluated for their insecticidal activity against Bactrocera cucurbitae (Diptera: Tephritidae) using a filter paper impregnated bioassay. The concentrations necessary to kill 50% (LC50 ) and 90% (LC90 ) of the flies in three hours were determined. The LC50 value was 0.23 ± 0.009 mg/cm2 and the LC90 value was 0.34 ± 0.015 mg/cm2 for the EO. The median lethal time (LT50 ) was determined to compare the toxicity of EO and the major constituents. The EO was the most potent insecticide (LT50  = 98 ± 2 min), followed by the mixture of myristicin and elemicin (1.4:1) (LT50  = 127 ± 2 min) indicating that the efficiency of the EO is potentiated by minor compounds and emphasizing one of the major assets of EOs against pure molecules.