Quantification of Total Phenolic and Carotenoid Content in Blackberries (Rubus Fructicosus L.) Using Near Infrared Spectroscopy (NIRS) and Multivariate Analysis.

Eva Toledo-Martín,Mercedes Del Río-Celestino,María Salinas-Navarro,José Moreno-Rojas,Pedro Gómez,María García-García,Rafael Font

doi:10.3390/molecules23123191

Abstract

A rapid method to quantify the total phenolic content (TPC) and total carotenoid content (TCC) in blackberries using near infrared spectroscopy (NIRS) was carried out aiming to provide reductions in analysis time and cost for the food industry. A total of 106 samples were analysed using the Folin-Ciocalteu method for TPC and a method based on Ultraviolet-Visible Spectrometer for TCC. The average contents found for TPC and TCC were 24.27 mg·g−1 dw and 8.30 µg·g−1 dw, respectively. Modified partial least squares (MPLS) regression was used for obtaining the calibration models of these compounds. The RPD (ratio of the standard deviation of the reference data to the standard error of prediction (SEP)) values from external validation for both TPC and TCC were between 1.5 < RPDp < 2.5 and RER values (ratio of the range in the reference data to SEP) were 5.92 for TPC and 8.63 for TCC. These values showed that both equations were suitable for screening purposes. MPLS loading plots showed a high contribution of sugars, chlorophyll, lipids and cellulose in the modelling of prediction equations.

Highlights

Consumers have high awareness of the health benefits of increased fruit and vegetable consumption, especially those rich in phytochemicals with nutraceutical properties
The objectives of the present work were: (i) to study the potential of the near infrared spectroscopy (NIRS) technology for predicting the total phenolic and total carotenoid contents in blackberries, being these compounds constituting some of the main responsible molecules of the antioxidant properties in this fruit; (ii) to provide some knowledge about the mechanism used by NIRS for successfully determining these compounds in the fruits of this species
Each 1.5 min we can analyse a sample for both quality components by using the NIR spectroscopy

Summary

Introduction

Consumers have high awareness of the health benefits of increased fruit and vegetable consumption, especially those rich in phytochemicals with nutraceutical properties. Vegetables and fresh fruit are reported to decrease the risk of cardiovascular diseases, certain forms of cancer and to prevent degenerative diseases [1,2]. This protection has been attributed to the fact that these foods may contain an optimal content of phytochemicals, such as antioxidants, fibre and other bioactive compounds [3]. These phytochemicals are in higher concentrations in small fruit, such as berries (blueberries, blackberries and strawberries) and this has motivated a large demand for fresh fruit. With reference to commercialization and sales prospects, the blackberry is the most promising reference [5,6]

Objectives

Results

Conclusion