Explorative study of apple juice fluorescence in relation to antioxidant properties

Total fluorescence spectra (excitation-emission matrices, EEM) were recorded for a series of commercial apple juices, including clear and cloudy juices produced from concentrate, cloudy juices that were not from concentrate, and freshly squeezed juices. An exploratory study of the spectra with parallel factor analysis (PARAFAC) revealed three groups of fluorophores with different emission properties, and these properties were characterized by excitation/emission maxima at 270/315 nm, (310, 370)/455 nm, and 430/(550, 680) nm, respectively.A regression analysis of the total fluorescence spectra arranged into three-way arrays using N-way partial least squares regression methods (NPLS1 and NPLS2) and an analysis of the unfolded spectra by partial least squares methods (PLS1 and PLS2) revealed quantitative relations between the fluorescence and antioxidant properties of juices. The best models for the total phenolic contents and total antioxidant capacities were obtained by applying the NPLS1 method to the EEM. The model parameters were as follows: R-CV(2) = 0.802, RPD = 2.3 for the total phenolic content and R-CV(2) = 0.808 and RPD = 2.3 for the total antioxidant capacity. These results show the potential use of fluorescence spectroscopy for screening apple juices for their antioxidant properties. (C) 2016 Elsevier Ltd. All rights reserved

Multivariate curve resolution Alternating least squares analysis of the total synchronous fluorescence spectra: An attempt to identify polyphenols contribution to the emission of apple juices

Presently we applied multivariate curve resolution alternating least squares (MCR-ALS) method for the analysis of front-face total synchronous fluorescence spectra (TSFS) of differently processed apple juices. This analysis enabled extracting of the TSFS profiles of five fluorescent components with distinct spectral characteristics and different contributions to the fluorescence of individual juices. Based on the spectral profiles and quantitative relationship with the chemical parameters describing the antioxidant properties of juices, three of the resolved components may be tentatively attributed to phenolic compounds. The analysis using multiple linear regression (MLR) and partial least square (PLS) regression confirmed better performance of fluorescence for the prediction of the total flavonoid content (TFC) as opposed to the total phenolic content (TPC) and total antioxidant capacity (TAC). This study demonstrated that MCR-ALS decomposition of the TSFS may provide a selective tool for understanding and interpretation of the observed relationships between the fluorescence and the total antioxidant indices of the apple juices

Inclusion of Life Cycle Thinking in a Sustainability-Oriented Consumer’s Typology: A Proposed Methodology and an Assessment Tool

Characterizing consumers in terms of their propensity to practice sustainable consumption represents an interesting research challenge in which a crucial role is played by the questionnaire in terms of its structure and classification criteria. Various classification rules have been proposed in the literature, which can be used to identify consumer types and signify their propensity to practice the principles of sustainable development in daily life. In this paper, we based our approach in designing a classification tool on a combination of two elements: the concept of voluntary simplicity as a pillar for consumer characteristics and the idea of assessing consumers by using filters, in a modified form introducing many new aspects of life-cycle thinking. The tool proposed provides insight into the relationship between the consumer’s typology and behavior during purchasing decisions in daily life. The main function of the proposed tool is to assign respondents to one of the proposed consumer types distinguished and characterized in terms of many aspects of life cycle thinking. A pilot survey has been performed in order to verify the proposed tool, and the survey results have been presented in the paper, as well