The present research attempts to characterize the effect of low temperatures, and the moisture content of maize (Kosmo 230) meant for sowing on its energy and capacity to germinate. Seeds were moistened to varying degrees and stored under various conditions; then, their germination energy and capacity were assessed. Sowing material with 15% moisture content showed slightly declined germination ability when stored at −25–−20 °C for over three days, while the storage of seeds with a 25 and 30% moisture content at −5–0 °C for 1–3 days had the effect of seed conditioning. Seedlings obtained from conditioned seeds showed sustainability characterized by faster growth, and demonstrated nearly twice the size as other plants. Warehousing and storage of maize grains with a 11.12% moisture content at temperatures up to −25 °C did not significantly affect seed germination capacity or energy, irrespective of storage time.
The purpose of this study was to determine the impact of the pomace drying methods (freeze-drying and convection-drying) and their percentage (0–10%) on selected physicochemical properties of gluten-free bread. The contents of nutrients (protein, fiber, fat, ash, and carbohydrates), bioactive compounds, antioxidant properties, acidity, baking efficiency, and moisture of the obtained products were determined. Fortifying the bread with raspberry pomace resulted in a change in fiber content from 18.13% d. b. (control sample) up to 19.97% d. b. (10% of freeze-dried pomace), and a change in the fat and ash content in the bread from 5.74% and 2.83% d. b. (control sample) to 7.18% and 3.12% d. b. (10% of freeze-dried pomace). The content of carbohydrates decreased after adding raspberry pomace to the bread, from 65.71% d. b. (control sample) to 63.68% d. b. (5% of freeze-dried pomace). The research carried out also showed that the introduction of 10% freeze-dried raspberry pomace increased the total polyphenol content by 81.75% and the antioxidant properties defined by the ABTS method by 159.54% and by the DPPH method by 96.43% compared to the control bread. The introduction of pomace resulted in a significant reduction in the total baking loss, from 15.1% to 10.62%, and an increase in the total titratable acidity of the crumb, from 2.13 mL NaOH/10 g d. b to 7.78 mL NaOH/10 g d. b. Principal component analysis highlighted a marked effect of the drying method and content of raspberry pomace on the quality values of gluten-free bread. This research demonstrated that raspberry pomace can be a valuable source of fiber and bioactive substances in gluten-free bread.
The study provides comprehensive information on the vacuum impregnation process applied to plant materials. It aims (in traditional applications) to ensure impermeability and elimination of porosity of various materials. The process substantially accelerates mass transfer in the liquid–solid system. The study describes the course of the process and accompanying phenomena as well its effects on plant tissues. The aim of the investigations was to determine the impact of some impregnation parameters (pressure, pressure change rate, vacuum maintenance time, relaxation time, and the coefficient of impregnating liquid viscosity) and the mode of impregnation (wet, dry, cyclic wet) on the degree of filling the plant tissue with the impregnating solution. Jonagold apples were used as the study material. The investigations have revealed that changes in the vacuum impregnation parameters (vacuum maintenance time, relaxation time, pressure change rate in the system) and the impregnation method do not exert a significant impact on the effectiveness of the process as expressed by the degree of permeation of the impregnating solution into the tissue. The pressure value and the viscosity coefficient were the only parameters that had a significant effect on the impregnation yield.
1 February 2020 in International Journal of Food Engineering
The aim of this work was to study the influence of freeze-drying conditions of kiwi (Actinidia deliciosa) on physicochemical properties and grinding characteristics of dried fruits. Whole kiwi fruits were freeze-dried with the different pressure: 12, 20, 42, 63, 85, and 103 Pa. Dried fruit properties that underwent evaluation included color, texture, rehydration, total phenolics content, antioxidant properties and sensory analysis. Moreover, the grinding energy indices of dried kiwi were determined. The results showed that an increase in the pressure caused decreased lightness, but increased yellowness and greenness of freeze-dried kiwi. The force of kiwi penetration increased and the rehydration ability decreased with the increase in the pressure. The specific grinding energy of dried kiwi ranged from 10.1 to 13.6 kJ⋅kg−1, whereas the average particle size of kiwi powder changed from 0.331 to 0.337 mm. The highest values of these parameters were obtained for kiwi freeze-dried with the highest pressure.
Cereal bars are so-called convenience foods. Consumers value these products as a healthier alternative to traditional chocolate bars. Since these snacks usually contain added dried fruit, they have high potential for the utilisation of waste materials from the fruit industry. The study aimed to determine the effect of fortification of cereal bars with grape and apple pomace on their nutritional value, physical properties, and sensory quality. The control recipe was modified by replacing 10 or 20 g of sultanas with apple or grape pomace. The fortification with these food by-products resulted in a significant increase in the moisture content of the products, an increase in soluble fibre content, and a decrease in the level of antioxidant compounds. The strength of the cereal bars supplemented with grape and apple pomace increased. In addition, the panellists noticed a colour difference compared to the unmodified product (2 < ΔE < 5). A positive effect of the addition of the fruit pomace on the visual characteristics of the cereal bars was also observed. No changes were observed in the tastiness of the product. On the other hand, the aroma of the modified products and the texture of the bars containing the apple residue were less acceptable. In conclusion, cereal bars containing grape pomace and up to 10 g of apple pomace are characterised by high soluble dietary fibre content and desirable sensory and mechanical properties and are therefore recommended for industrial production.
Red raspberries, which contain a variety of nutrients and phytochemicals that are beneficial for human health, can be utilized as a raw material in the creation of several supplements. This research suggests micronized powder of raspberry pomace production. The molecular characteristics (FTIR), sugar, and biological potential (phenolic compounds and antioxidant activity) of micronized raspberry powders were investigated. FTIR spectroscopy results revealed spectral changes in the ranges with maxima at ~1720, 1635, and 1326, as well as intensity changes in practically the entire spectral range analyzed. The discrepancies clearly indicate that the micronization of the raspberry byproduct samples cleaved the intramolecular hydrogen bonds in the polysaccharides present in the samples, thus increasing the respective content of simple saccharides. In comparison to the control powders, more glucose and fructose were recovered from the micronized samples of the raspberry powders. The study’s micronized powders were found to contain nine different types of phenolic compounds, including rutin, elagic acid derivatives, cyanidin-3-sophoroside, cyanidin-3-(2-glucosylrutinoside), cyanidin-3-rutinoside, pelargonidin-3-rutinoside, and elagic acid derivatives. Significantly higher concentrations of ellagic acid and ellagic acid derivatives and rutin were found in the micronized samples than in the control sample. The antioxidant potential assessed by ABTS and FRAP significantly increased following the micronization procedure.