Impact of germination on the techno-functional properties, nutritional composition, and health-promoting compounds of brown rice and its products: A review.

Rice is a popular grain and forms part of the daily diet of people throughout the world. However, the consumption of rice and its products is sometimes limited by its high glycemic index due to its high starch content, low protein content and quality, and low bioavailability of minerals due to the presence of anti-nutritional factors. This has partly stimulated research interest in recent times toward the use of bioprocessing techniques such as germination as cheap and natural means to improve the nutritional quality, digestibility, and health properties of cereals, including rice, to partially achieve nutrition and food security in the developing regions of the world. This review highlights the impact of germination on the nutritional quality, health-promoting properties, and techno-functional characteristics of germinated brown rice grains and their products. The review demonstrated that germinated rice grains and their products have improved nutritional quality and digestibility, modified functional properties, and showed antioxidant, anti-inflammatory, anti-diabetic, anti-obesity, anti-cancer, and anti-cardiovascular activities. Germination appears to be a suitable bioprocessing method to improve the nutritional quality and bioactive constituents and modify the techno-functional properties of rice grains for diverse food applications and improved global nutrition and food safety.

Nutritional and physicochemical changes in two varieties of fonio (Digitaria exilis and Digitaria iburua) during germination.

Germination is a cheap and effective bioprocessing technique used for improvement of the nutritional, physicochemical and health-promoting properties of seeds. The benefits of germination on two fonio varieties (Digitaria exilis and Digitaria iburua) have not been studied. This study investigated the nutritional and physicochemical changes in two varieties of fonio germinated for 24, 48 and 72 h at 28 °C. The antioxidant, protein and starch digestibility, functional, pasting, and thermal properties were also determined. Germination over time (24, 48, 72 h) significantly (p ≤ 0.05) increased the protein, ash, total dietary fiber, majority of the amino acids, minerals, protein digestibility, resistant starch, total phenolics and antioxidant activities while phytic acid, tannin, saponin and digestible starch contents decreased in both varieties. Germination significantly increased water and oil absorption capacity, and slightly modified pasting and thermal characteristics while bulk density decreased in both varieties. The principal component analysis revealed germination time to be the key determinant in the physicochemical, nutritional, and techno-functional characteristics of fonio rather than variety, with raw and 24 h germinated grains having similar attributes. The study established that germination improved the nutritional, antioxidant, and techno-functional properties of Digitaria exilis and Digitaria iburua, which can serve as novel food ingredients for product development.

Influence of Seed Variety and Extraction Technique on Fatty Acid Distribution and Quality Parameters of Tropical Castor (Ricinus communis L.) Oils.

Industrial application of castor oil is anchored on both agronomical and technological variables that intrinsically influence its quality properties. Therefore, castor oils of two varieties (Gibsoni and Carmenicita), extracted by screw press, solvent and traditional methods were compared in terms of oxidative stability indices, quality parameters and fatty acid distributions. General factorial analyses showed the significance of both factors on the oil yield, color intensity, moisture content, oxidative stability indices, most of the oil's fatty acids and other quality parameters. Gibsoni variety yielded more oil at the range of 40.12 - 53.51%, especially in solvent extraction. The two oxidative stability indicators; peroxide value (PeV) and free fatty acids (FFA) favored traditional extraction and were significantly higher in oils of Carmenicita variety, at 4.26 - 7.21 meqO2/kg and 2.55 - 3.94%, respectively. In addition to ricinoleic acid (85.93 - 89.19%), other fatty acids characterized in the oils include, oleic (4.73 - 5.84%), stearic (1.41 - 2.50%), linoleic (1.08 - 3.41%), and palmitic acids (0.60 - 1.29%). Saponification (SaV) and iodine values (IoV) of the oils were unaffected by varietal differences or extraction processes and the ranges recorded in both varieties were within ASTM (175 - 187 mgKOH/g) and EN 14214 (120-140 g I2/100 g) acceptable limits. Principal component analysis (PCA) model built on the data of the oils further emphasized the significance of these two factors in quality characterization of castor oil.

Near Infrared Spectroscopy as a Green Technology for the Quality Prediction of Intact Olives.

Poorly emphasized aspects for a sustainable olive oil system are chemical analysis replacement and quality design of the final product. In this context, near infrared spectroscopy (NIRS) can play a pivotal role. Thus, this study aims at comparing performances of different NIRS systems for the prediction of moisture, oil content, soluble solids, total phenolic content, and antioxidant activity of intact olive drupes. The results obtained by a Fourier transform (FT)-NIR spectrometer, equipped with both an integrating sphere and a fiber optic probe, and a Vis/NIR handheld device are discussed. Almost all the partial least squares regression models were encouraging in predicting the quality parameters (0.64 < R2pred < 0.84), with small and comparable biases (p > 0.05). The pair-wise comparison between the standard deviations demonstrated that the FT-NIR models were always similar except for moisture (p < 0.05), whereas a slightly lower performance of the Vis/NIR models was assessed. Summarizing, while on-line or in-line applications of the FT-NIR optical probe should be promoted in oil mills in order to quickly classify the drupes for a better quality design of the olive oil, the portable and cheaper Vis/NIR device could be useful for preliminary quality evaluation of olive drupes directly in the field.

Effects of malaxation temperature and harvest time on the chemical characteristics of olive oils.

The aim of the study was to determine the effects of harvest time and malaxation temperature on chemical composition of olive oils produced from economically important olive varieties with a full factorial experimental design. The oils of Ayvalik and Memecik olives were extracted in an industrial two-phase continuous system. The quality parameters, phenolic and fatty acid profiles were determined. Harvest time, olive variety and their interaction were the most significant factors. Malaxation temperature was significant for hydroxytyrosol, tyrosol, p-coumaric acid, pinoresinol and peroxide value. Early and mid-harvest oils had high hydroxytyrosol and tyrosol (maximum 20.7mg/kg) and pigment concentrations (maximum chlorophyll and carotenoids as 4.6mg/kg and 2.86mg/kg, respectively). Late harvest oils were characterized with high peroxide values (9.2-25meqO2/kg), stearic (2.4-3.1%) and linoleic acids (9.3-10.4%). Multivariate regression analysis showed that oxidative stability was affected positively by hydroxytyrosol, tyrosol and oleic acid and negatively by polyunsaturated fatty acids.