The Nutritional Characterization of Rice Varieties Consumed in Portugal

Poster Reference Number: PO2580

Background and objectives: Portugal has the largest consumption of rice 15.8 kg/capita/year, in Europe. The present work aims to evaluate: rice nutritional profile, namely proximate, amino acid and mineral composition; arsenic content, as the most abundant contaminant and, compositional differences between varieties, year and place of harvest. Methods: Samples were collected from the most representative national rice producers. Analysis was carried out by following analytical methods: proximate by AOAC methods; amino acids by UPLC-DAD; starch, and amylase by enzymatic methods; mineral analysis by ICP-OES including copper, manganese, iron, zinc, magnesium, calcium, sodium, phosphorus and potassium and arsenic content by ICP-MS. Results: Analyzed rice showed higher amylopectin (54.7 ± 7.3 g/100g) content than amylose (33.5± 3.8 g/100g) and total protein content of 7.1 ± 0.3 g/100g a low content of fiber and fat (<1 g/100 g) was found. The most abundant essential amino acids were aromatic amino acids with a 7.5% of total protein. The most abundant minerals were potassium and phosphorus with levels ranging from 91 mg/100g to 107 mg/100g.The arsenic content was determined by ICP-MS and the values were below 600 µg/kg. Conclusions: Crop place showed to be the major source of variation in amino acid content. With respect to protein quality, cysteine, lysine, sulfur amino acids and isoleucine were considered limiting with protein digestibility corrected amino acids scores (PDCAAS) lower than 1. To assure the nutritional requirements for amino acids and subsequent protein synthesis, rice consumption must be followed by other food groups (e.g pulses, meat products) in order to provide the other essential amino acids. Rice contribution for mineral intake ranged from 3% DRI (iron and potassium) to 36 % DRI (manganese). In this study, a very weak correlation between arsenic levels and amino acid content was observed.