SENSORY AND INSTRUMENTAL ANALYSIS OF THE JUICINESS OF STRAWBERRIES

Modelling strawberry quality in a longitudinal study under the marketing concept of branding

Background

Marketing strategies, such as branding, redefine how consumers perceive quality and create new requirements related to season length and quality homogeneity, among others. For short-day (SD) strawberry cultivar brands, the commercial season is short due to a dependency on temperature and photoperiod. A plausible strategy to extend the commercialization period is to use different varieties within a single brand; however, this has led to inconsistent quality in other fruit crops. A form of quality assessment to evaluate the impact of a multi-varietal brand on sensory quality is a critical longitudinal study with several sources of variability, such as the inherent variation among assessors and fruit replicates that can affect the reliability of the results. Therefore, this study aimed to develop a methodology to assess the sensorial and physicochemical quality of strawberry brands in two contexts: a short-term season composed of two SD cultivars and a long-term season with one SD and one day-neutral (DN) cultivar.

Results

New statistical models are proposed in this study. An ANOVA mixed model with assessors and replicates as random terms and a multiple factor analysis highlighted a lack of homogeneity with regard to texture parameters and sourness, while partial least square models identified aroma and sweetness as the best quality indicators.

Conclusions

This work has successfully illustrated a methodology that is capable of handling critical aspects of longitudinal studies by using univariate models that account for different sources of variability and constrained multivariate models to relate parameters with overall liking. A long-term brand is a viable solution to valorise strawberries, as parameter heterogeneity did not affect overall quality.

A Comparison of Temporal Dominance of Sensation (TDS) and Quantitative Descriptive Analysis (QDA™) to Identify Flavors in Strawberries

Temporal dominance of sensations (TDS) is a rapid descriptive method that offers a different magnitude of information to traditional descriptive analysis methodologies. This methodology considers the dynamic nature of eating, assessing sensory perception of foods as they change throughout the eating event. Limited research has applied the TDS methodology to strawberries and subsequently validated the results against Quantitative Descriptive Analysis (QDA™). The aim of this research is to compare the TDS methodology using an untrained consumer panel to the results obtained via QDA™ with a trained sensory panel. The trained panelists (n = 12, minimum 60 hr each panelist) were provided with six strawberry samples (three cultivars at two maturation levels) and applied QDA™ techniques to profile each strawberry sample. Untrained consumers (n = 103) were provided with six strawberry samples (three cultivars at two maturation levels) and required to use TDS methodology to assess the dominant sensations for each sample as they change over time. Results revealed moderately comparable product configurations produced via TDS in comparison to QDA™ (RV coefficient = 0.559), as well as similar application of the sweet attribute (correlation coefficient of 0.895 at first bite). The TDS methodology however was not in agreement with the QDA™ methodology regarding more complex flavor terms. These findings support the notion that the lack of training on the definition of terms, together with the limitations of the methodology to ignore all attributes other than those dominant, provide a different magnitude of information than the QDA™ methodology.

PRACTICAL APPLICATION

A comparison of TDS to traditional descriptive analysis indicate that TDS provides additional information to QDA™ regarding the lingering component of eating. The QDA™ results however provide more precise detail regarding singular attributes. Therefore, the TDS methodology has an application in industry when it is important to understand the lingering profile of products. However, this methodology should not be employed as a replacement to traditional descriptive analysis methods.

Supporting young researchers in food texture studies

I learned about food texture by reading many articles in the Journal of Texture Studies (JTS) and Prof. Bourne's textbook Food Texture and Viscosity, Concept and Measurement. I present here his great contributions as both the Editor-in-Chief of JTS and as the author of a superior textbook in the cultivation of future food texture researchers. Prof. Bourne has provided significant guidance to those in the industry using his textbook to suggest appropriate approaches to measure, evaluate, and alter the textures of agro-products and processed foods. I began my career in food rheology, learned the physiological techniques necessary for measuring mastication, and developed relationships with good sensory scientists along the way. I am happy to offer advice to agriculture and food scientists, researchers, and engineers in the food industry regarding food texture. I would like to be a follower of Prof. Bourne and support young food texture scientists in the 21st century.

PRACTICAL APPLICATIONS

Food texture studies conducted during the last century are beginning to evolve. Based on previous publications in the Journal of Texture Studies, I believe that several areas can be further examined in this century. First, methods to evaluate the textures of heterogeneous materials, such as fruits and vegetables, require improvements. Second, the monitoring of rapid changes in food texture during oral processing should be considered during the design of food products. Third, a new instrumental method that mimics the movement and breakdown of soft foods by the tongue is being developed. The optimization of food processing to reduce the loss of agro-products and production of high-quality foods both require more attention according to the Sustainable Development Goals adopted by the United Nations in 2015.