Gluten-Free Crackers Based on Chickpea and Pumpkin Seed Press Cake Flour: Nutritional, Functional and Sensory Properties.

Research background: Despite the growing trend of the gluten-free market and the presence of a wide range of gluten-free products, there are still some shortcomings in nutritional and sensory quality of these products. The commercially available gluten-free products are characterised as products of inferior nutritional quality, particularly in terms of protein and dietary fibre content and with high glycaemic index. On the other hand, from a sensory point of view, gluten-free products usually have inappropriate textural and mechanical properties, poor mouthfeel and flavour. This is a consequence of the limiting choice of raw materials that mainly possess large amount of carbohydrate components. Experimental approach: Chickpea flour and two types of pumpkin seed press cake flour (virgin and cold pressed), at two substitution mass fractions (20 and 35%), were blended to produce gluten-free crackers without the presence of conventional gluten-free starch-rich ingredients. This study aims to investigate the effect of these non-conventional flours on nutritional and physicochemical properties, sensory acceptability, antioxidant activity and glycaemic index of crackers. Results and conclusions: All produced crackers can bear nutritional claims 'high fibre', 'source of protein' and 'source of minerals'. Replacing chickpea flour with pumpkin seed press cake flour increased protein and total phenolic content and enhanced antioxidant activity. The selected combination of raw materials allows the production of gluten-free crackers with a moderate glycaemic index. Besides nutrient content, the addition of cold-pressed flour increased overall sensory acceptability, noticeably improving taste and flavour scores compared to the control and crackers with virgin pumpkin seed flour. Novelty and scientific contribution: To the best of our knowledge, there is no study investigating the use of chickpea and pumpkin seed press cake flour blend without using conventional gluten-free flour and starch. The used non-conventional flour represents complementary raw materials in terms of protein quality and valuable alternatives to produce nutrient-rich, health-promoting gluten-free crackers with reduced glycaemic response and acceptable sensory properties.

Comparative study of nutritional and technological quality aspects of minor cereals.

In order to have a better insight into the quality of minor cereals, the aim of this research was to evaluate the nutritional, biochemical, physical and rheological properties of barley, rye, triticale, oat, sorghum and millet flours. Generally, all flours could be divided into two groups according to mineral content, ω-6/ω-3 fatty acids ratio and amino acid composition. Sorghum flour was characterized by the highest total phenolic content and was the only flour which contained detectable amounts of tannins. Sorghum and millet flours differed from other flours by lower water absorption index and higher temperature of starch gelatinization. Additionally, sorghum and millet flours could be analysed by Mixolab only using constant hydration and require more time to obtain complete hydration than other flours. All flours would require modification of standard breadmaking process in order to obtain quality of product similar to those already present at the market.

Vegetable By-Products as New Sources of Functional Proteins.

Vegetable by-products, obtained from cauliflower (CA), broccoli (BRL), cabbage (CB) and beetroot (BR) can be a potentially good source of proteins. The proteins were obtained from leaves (LPs) of vegetables with alkaline extraction at pH 10, and their isoelectric precipitation at pH 4. Protein contents were in the range of 39.76 - 53.33%, and the molecular weights of fractions were mostly about 45, 25 and 14 kDa. Their solubility is higher in the alkaline environment, where they reach the highest solubility at pH 10 (9.7 mg/mL for CALP, 8.45 for BRLP, 5.35 mg/mL for CBLP, 5.5 mg/mL for BELP). Moreover, they showed favorable emulsifying abilities, water absorption capacities (0.62 to 1.61 g/g) and foaming capacity (86.3 to 92%) as well as stability (48.57 to 79.30%). Digestibility was studied using gastrointestinal proteases (pepsin and pancreatin), and all four LPs can easily be digested. The biologically active potential of the digests was evaluated measuring antioxidant capacity by two complementary methods - DPPH+ and ABTS+ radical cation scavenging activity. The values for DPPH+ and ABTS+ were in the range from 59 to 65.1% at 0.1 and 0.3 mg/ml to 0.22 mg/ml IC50 values, respectively. Therefore, it can be indicated from these results, that obtained LPs, owing to their good functional properties, may be considered as potential ingredients of health-promoting food and cosmetic products.

Heat and hydrothermal treatments of non-wheat flours.

Non-wheat cereals have become popular in the diet due to their nutritional benefits, but their application is limited by properties of their proteins. Some of these flours can be conventionally processed, but the final products are not of acceptable quality. Modification of physico-chemical properties of non-wheat flours by dry heat and extrusion represent the alternative process which can transform the flours into an adequate raw material for the bakery and confectionery industry. The aim of this study was to determine the type and extent of physico-chemical changes in modified flours whose mixtures were used successfully for bread production. Extrusion had stronger influence on chemical composition of flours than dry heating, especially on the content of fats and phenolic compounds. Extrusion also increased starch digestibility due to complete gelatinization process, making it almost equal for all flours. On the other hand, protein digestibility depends mostly on botanical origin of flour.

Encapsulation of beetroot juice: a study on the application of pumpkin oil cake protein as new carrier agent.

Aim: In the present study, beetroot juice was encapsulated in pumpkin protein isolate by freeze and spray drying method.Methods: The powders were characterised by measuring moisture content, hygroscopicity, bulk density, solubility, a* value (colour). To simulate the human gastrointestinal digestion, in vitro digestion was conducted as two-stage hydrolysis by pepsin and by pancreatin. The antioxidant and ACE inhibitory potential of the digests was examined.Results: Encapsulation efficiency of phenols from beetroot juice in pumpkin protein isolate was 92% for freeze and 75% for spray dried. Physical properties of all samples were affected by the drying methods. All powders were easily digested. It was observed that the antioxidant and ACE inhibitory potential of the digests was enhanced, indicating that it originated from the hydrolysates released from the protein carrier during digestion.Conclusion: The results from this study are promising and indicate that the pumpkin oil cake protein has great potential and could be introduced to the encapsulation process of bioactive compounds as a new carrier agent.

Production of Bio-Functional Protein through Revalorization of Apricot Kernel Cake.

The study describes and compares bio-functional properties and thein vitrodigestibility of protein isolates from apricot oil cakes obtained by supercritical fluid extraction and cold pressing, as control. Protein isolates have the potential to be food ingredients with amygdalin contents in an amount considerably lower than regulatory. Isolates showed hypoglycemic activity, studied by the inhibition of α-glucosidase, also functional properties were determined.Good digestibility of proteins, which were done using gastrointestinal proteases (pepsin and pancreatin) were proven by Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis SDS-PAGE analysis. Moreover, it was evident that the protein isolates were completely digested. The biologically active potential of the digests was evaluated measuring in vitro antioxidant capacity by three complementary methods and enzyme inhibitory effects towards Angiotensin-I Converting Enzyme (ACE) related with the onset of hypertension. All hydrolysates act as a DPPH and ABTS scavenger, as a reducing agents and an ACE enzyme inhibitor. In conclusion, protein isolates obtained from apricot kernel cake showed to be a promising source of natural products for food applications, with good functional and bioactive properties and easy digestibility.

Subcritical Water for Recovery of Polyphenols from Comfrey Root and Biological Activities of Extracts.

In the present study, subcritical water was used for extraction of bioactive compounds of Symphytum officinale root. Temperature (120-200 °C), extraction time (10-30 min) and HCl concentration in extraction solvent (0-1.5%) were investigated as independent variables in order to obtain the optimal conditions for extraction and to maximize the yield of total phenols, flavonoids and antioxidant activity of obtained extracts. The application of optimal conditions (200 °C, 25.6 min and 0.0075%) provided extracts rich in total phenols and flavonoids and high antioxidant activity. Results also demonstrated that subcritical water extraction showed significant advantages for recovery of comfrey root bioactive compounds comparing to maceration and ultrasound-assisted extraction techniques. In addition, subcritical water extracts of S. officinale root are the promising sources of compounds with antioxidant, ACE inhibition, and antiproliferative properties and could potentially be used for production of new pharmacologically-active formulations.

Modeling and optimization of red currants vacuum drying process by response surface methodology (RSM).

Fresh red currants were dried by vacuum drying process under different drying conditions. Box-Behnken experimental design with response surface methodology was used for optimization of drying process in terms of physical (moisture content, water activity, total color change, firmness and rehydratation power) and chemical (total phenols, total flavonoids, monomeric anthocyanins and ascorbic acid content and antioxidant activity) properties of dried samples. Temperature (48-78 °C), pressure (30-330 mbar) and drying time (8-16 h) were investigated as independent variables. Experimental results were fitted to a second-order polynomial model where regression analysis and analysis of variance were used to determine model fitness and optimal drying conditions. The optimal conditions of simultaneously optimized responses were temperature of 70.2 °C, pressure of 39 mbar and drying time of 8 h. It could be concluded that vacuum drying provides samples with good physico-chemical properties, similar to lyophilized sample and better than conventionally dried sample.