Engineering properties and optimization of the dehulling process for hairless canary seed.

 This work aimed to determine the engineering properties of hairless canary seeds (Phalaris canariensis L.) of the variety "CDC Maria" and the optimum combination of operating conditions of the dehulling process with a pilot-scale centrifugal dehuller. The engineering properties analyzed in this study were the principal dimensions, length (4.8 mm), width (1.95 mm) and thickness (1.41 mm); geometric mean diameter (2.36 mm); the sphericity (49.2%); apparent and true densities (752 and 1191.47 kg/m3, respectively); the porosity (0.37); 1000 grains weight (7.28 g); angle of repose (15.89°) and the static coefficient of friction (galvanized steel, 0.325; plywood, 0.372; aluminium, 0.316). For the process optimization, a two-variable Doehlert design was used, analyzing the effect of impact dehuller rotor speed (peripheral speed 30.4 to 47.1 m/s) and seed moisture content (10 to 14% d.b.) by maximizing the dehulling ability (DA) and maintaining the production of fines by 3%. Under the experimental conditions of 36.7 m/s (peripheral speed) and 10% d.b. (seed moisture), with a double pass through the dehuller, the optimum value of DA (94%) was obtained, with a fine production of 3%. The optimized dehulling process allows removing a large percentage (98%) of the canary seed hull.

Optimization of mucilage extraction from chia seeds (Salvia hispanica L.) using response surface methodology.

BACKGROUND: Chia mucilage has potential application as a functional ingredient; advances on maximizing its extraction yield could represent a significant technological and economic impact for the food industry. Thus, first, the effect of mechanical agitation time (1-3 h) on the exudation of chia mucilage was analyzed. Then, response surface methodology was used to determine the optimal combination of the independent variables temperature (15-85 °C) and seed: water ratio (1: 12-1: 40.8 w/v) for the 2 h exudation that give maximum chia mucilage yield. Experiments were designed according to central composite rotatable design. RESULTS: A second-order polynomial model predicted the variation in extraction mucilage yield with the variables temperature and seed: water ratio. The optimal operating conditions were found to be temperature 85 °C and a seed: water ratio of 1: 31 (w/v), reaching an experimental extraction yield of 116 ± 0.21 g kg-1 (dry basis). The mucilage obtained exhibited good functional properties, mainly in terms of water-holding capacity, emulsifying activity, and emulsion stability. CONCLUSION: The results obtained show that temperature, seed: water ratio, and exudation time are important variables of the process that affect the extraction yield and the quality of the chia mucilage, determined according to its physicochemical and functional properties. © 2018 Society of Chemical Industry.

Development and characterization of functional O/W emulsions with chia seed (Salvia hispanica L.) by-products.

The present work investigated the physicochemical properties of O/W emulsions containing functional ingredients (oil with high ω-3 fatty acid content, protein and/or soluble fiber) from chia seeds. The effect of different protein-carbohydrate combinations (sodium caseinate and lactose, sodium caseinate and maltodextrin, chia protein-rich fraction and maltodextrin) and the presence of chia mucilage (0 and 0.2 % wt/wt) in the aqueous phase of chia O/W emulsions was studied as a function of droplet size distribution, Sauter mean diameter, ζ-potential, rheological properties and backscattering profiles. The use of sodium caseinate in combination with lactose or maltodextrin produced chia O/W emulsions with small droplet size (0.22-0.27 µm), high degree of uniformity in droplet size distribution, negatively charged droplets (at pH 6.5), pseudoplastic behavior and high physical stability. Emulsions with chia protein-rich fraction presented wider droplet size distribution and higher D[3,2] values than the previous ones, recording a Newtonian behavior. The addition of chia mucilage affected the physicochemical properties studied, mainly the rheological characteristics of emulsions.

Microstructure, chemical composition and mucilage exudation of chia (Salvia hispanica L.) nutlets from Argentina.

BACKGROUND: The micromorphology and anatomy of nutlets, myxocarpy (mucilage exudation) and mucilage structure of Argentinean chia were described using scanning electron microscopy (SEM). The proximal composition of nutlets and mucilage was also studied. RESULTS: Chia nutlets are made up of a true seed and a pericarp enclosing the seed; they are small, glabrous, elliptic and apically rounded. The pericarp has cuticle, exocarp, mesocarp and bone cells vertically arranged and endocarp. The myxocarpy was carefully recorded by SEM. After 5 min in contact with water, the cuticle of nutlets is broken and the exocarp cell content gradually surrounds the rest of the nutlet. The proximal composition of chia nutlets was studied; fat is the major component (327 ± 8.0 g kg(-1)) followed by protein (293 ± 4.0 g kg(-1)) and fiber (276 ± 1.0 g kg(-1)). Extractions of chia nutlets with water at room temperature yielded 38 ± 1.0 g kg(-1) (dry basis) of mucilage. The fresh mucilage structure was similar to a network of open pores. The freeze-dried crude mucilage contained more ash, residual fat and protein than commercial guar and locust bean gum. The solubility of 10.0 g L(-1) w/v solution of chia freeze-dried crude mucilage in water increased with temperature, being maximal at 60 °C (870 g kg(-1)). CONCLUSION: The results obtained show a fast exudation of chia mucilage when nutlets are in contact with water. The freeze-dried crude mucilage hydrates easily in water, even at low temperatures. Chia nutlets have mucilaginous substances, with interesting functional properties from a technological and physiological point of view.

Effect of Drying Operating Conditions on Canola Oil Tocopherol Content.

The aim of this work was to evaluate two operating parameters of seed drying (temperature and initial moisture content) on the tocopherol content of canola oil. The raw material was characterized by moisture, oil, protein, crude fiber and ash content. Seeds at 13.6% and 22.7% moisture content (dry basis, db) were dried at temperatures in the range of 35-100 °C to a safe storage moisture of 7% db. Oil was extracted from each treated sample. The oil extracted from the samples dried at the extreme temperatures was analyzed by means of the acidity value, peroxide index and fatty acid composition, finding no significant differences among treatments or among untreated and treated samples. Tocopherol contents in the oils obtained for all the assayed temperatures were determined. Differences were found for the samples with 22.7% (db) initial moisture content. Except at 35 °C, temperature affected negatively the oil tocopherol content. However, when 13.6% (db) moisture seeds were processed, no significant differences were observed in the amount of this minor oil component among assays.