The existing methodologies for determining thresholds generate unreliable estimates of the point at which the intensity of a stimulus begins to compromise acceptance or result in sensory rejection of a product. Thus, a new methodology was proposed for determination of two new sensory thresholds: the compromised acceptance threshold (CAT) and the rejection threshold (RT). In this new methodology, increasing or decreasing series of stimulus intensity are measured together with a standard stimulus (control sample) by means of acceptance tests. In the present study, the CAT and RT were determined for sucrose concentrations in grape nectar, demonstrating that when reducing the sucrose concentration of grape nectar form 9.00% (w/v) to 6.87% there begins to occur impairment of product acceptance (CAT), and when reducing the sucrose concentration from 9.00% to 3.83% there begins to occur sensory rejection (RT) of the product. When compared to existing threshold determination methodologies, the proposed methodology permitted for calculating, with greater reliability, the points at which compromise of acceptance (CAT) and sensory rejection (RT) of the product begin to occur. In addition to the case study presented, the proposed methodology has a wide range of applications in science and in the food, cosmetic and pharmaceutical industries.

The compromised acceptance threshold (CAT) indicates the intensity of a stimulus from which product acceptance is significantly altered. This new affective threshold is determined by hedonic threshold methodology (HTM). The levels of analytical performance associated with precision (repeatability, intermediate precision, and reproducibility), accuracy, and robustness of CAT results were investigated. The methodology met the pre-established criteria, being accurate in assessments carried out consecutively (repeatability), in tests separated by a certain period of time as well as with different consumer panels (intermediate precision), and in tests carried out in different facilities (reproducibility). The methodology presented suitable accuracy, though slightly conservative, which may be desirable. The methodology was also shown to be robust as it allowed the reduction of panel members from 150 to 70 consumers. In this context, the methodology-which presented reliable results as well as high precision, accuracy, and robustness-was validated. Practical applicationsThe need for showing the quality of sensory measurements is being increasingly recognized and required for the acceptance of new methodologies within the scientific community, given that unreliable analytical data may lead to dreadful decisions as well as long-lasting financial losses.Results from the present work show that the data obtained through the hedonic threshold methodology/compromised acceptance threshold methodology met all criteria of the evaluated analytical indexes. Thus, one may conclude that this methodology has suitable precision (repeatability, intermediate precision, and reproducibility), accuracy, and robustness (by reducing consumer panel size) levels and is efficient in providing reliable results. Hence, this method can be applied for the intended purpose.

The hedonic thresholds methodology was recently proposed which allows for determination of two new sensorial thresholds, the compromised acceptance threshold and the hedonic rejection threshold (HRT). For a new methodology to be accepted by the scientific community, its ability to produce reliable results must be demonstrated. Thus, this study sought to validate this new methodology when used to calculate the HRT. In order to do so, the analytical performance indices of precision (repeatability, intermediate precision, and reproducibility), accuracy and robustness for the results for the HRT calculation were measured. The results of seven experiments demonstrated that the methodology possesses high repeatability, intermediate precision and robustness, and satisfactory accuracy and reproducibility. It was therefore concluded that the HRT determination methodology satisfactorily met the analytical performance criteria evaluated, therefore generating reliable results. Practical applications The hedonic thresholds methodology (HTM) has numerous applications, including the application of a more severe thermal treatment to obtain greater microbial or enzymatic inactivation, the determination of food shelf life based on its sensory acceptance, the reduction of specific, expensive ingredients in food formulations, reduction of ingredients that are harmful to health when consumed in excess (e.g., sucrose, sodium, and fat), determination of the maximum “defect” threshold that may be present in food and others. The HTM is a recently proposed methodology; therefore, the reliability of the values of the hedonic rejection threshold must be validated, calculated via the HTM. Reliability of the HRT results was confirmed when HTM validation was performed. Thus, the methodology can undoubtedly be applied for the intended purpose.

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