Modelling the vigour of maize seeds submitted to artificial accelerated ageing based on ATR-FTIR data and chemometric tools (PCA, HCA and PLS-DA).

The main goals of this research were to use ATR-FTIR spectroscopy associated with multivariate analyses to identify biochemical changes in high and low vigour seed tissues (embryo and endosperm) in response to accelerated ageing and to create a model to predict seed vigour based on spectroscopic data. High-vigour seeds undergo minimal changes in biochemical composition during stress by accelerated ageing while low-vigour seeds are more sensitive to stress and this lower tolerance is associated with reduced lipid and protein content and increased amino acids, carbohydrates and phosphorus compounds in the embryo. High-vigour seeds show an increase in peaks associated with amino acids and phosphorous compounds in the endosperm after 24 h of stress while low-vigour seeds present these high-intensity peaks only after 72 h in the embryo. The results of this research provide the theoretical basis for the genetic improvement of maize cultivars that aim at higher physiological seed quality.

Germination in Optimal Conditions as Effective Strategy to Improve Nutritional and Nutraceutical Value of Underutilized Mexican Blue Maize Seeds.

Germination of grains is a bioprocess of emerging interest to improve nutritional and nutraceutical profile of cereals in a natural way. The aim of this work was to identify optimal germination conditions (temperature/duration) for producing a functional blue maize flour with maximum values of protein content (PC), antioxidant activity (AoxA), and total phenolic and anthocyanin contents (TPC, TAC). A central composite rotatable experimental design (response surface methodology) with two factors [Germination temperature (Gtemp, 20-40 °C) / Germination duration (Gdur, 12-220 h)] in five levels was used (13 treatments). Blue maize seeds were soaked in distilled water (25 °C / 12 h) before germination. The sprouts were dried, tempered (25 °C), and ground to obtain germinated blue maize flours (GBMF). The prediction models developed for each response variable showed high coefficients of determination, demonstrating their adequacy to explain the variations in experimental data. Maximum values of PC, AoxA, TPC, and TAC were attained at Gtemp = 26.9 °C / Gdur = 207.7 h. Optimized germinated blue maize flour (OGBMF) presented higher PC (+38.48%), AoxA (ABTS: +192%, ORAC: +160%, DPPH: +148%), TPC (+79%), and TAC (+9.9%) than unprocessed blue maize flour (UBMF). Germination at optimal conditions is an effective strategy to increase the nutritional/nutraceutical quality of blue maize seeds, thus the flour of these germinated seeds could be used for the development of functional foods.