The influence of the extrusion process on the nutritional composition, physical properties and storage stability of black chokeberry pomaces

Properties of Biocomposites Made of Extruded Apple Pomace and Potato Starch: Mechanical and Physicochemical Properties

This paper presents research results on biocomposites made from a combination of extruded apple pomace (EAP) and potato starch (SP). The aim of this work was to investigate the basic properties of biocomposites obtained from extruded apple pomace reinforced with potato starch. The products were manufactured by hot pressing using a hydraulic press with a mould for producing samples. The prepared biocomposites were subjected to strength tests, surface wettability was determined, and a colour analysis was carried out. A thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and cross-sectioning observed in a scanning electron microscope (SEM) were also performed. The obtained test results showed that the combination of apple pomace (EAP) and starch (SP) enabled the production of compact biocomposite materials. At the same time, it was found that each increase in the share of starch in the mixture for producing biocomposites increased the strength parameters of the obtained materials. With the highest share of starch in the mixture, 40%, and a raw material moisture content of 14%, the material had the best strength parameters and was even characterised by hydrophobic properties. It was also found that materials with a high content of starch are characterised by increased temperature resistance. The analysis of SEM microscopic photos showed well-glued particles of apple pomace, pectin, and gelatinised starch and a smooth external structure of the samples. Research and analyses have shown that apple pomace reinforced only with the addition of starch can be a promising raw material for the production of simple, biodegradable biocomposite materials.

Fresh Chokeberry (Aronia melanocarpa) Fruits as Valuable Additive in Extruded Snack Pellets: Selected Nutritional and Physiochemical Properties

In this paper, the nutritional value and (selected) physiochemical properties of extruded snack pellets enriched with fresh chokeberry (Aronia melanocarpa) fruits were analyzed from the perspective of being a new product for the functional food sector. The purpose of this study was to determine the effect of the addition of fresh chokeberry and variation in content and screw speed on extruded snack pellet basic compositions, fatty acid profiles, antioxidant activity, as well as water absorption and solubility indexes, fat absorption and color profiles. The obtained results revealed a significant increase in antioxidant activity for all samples (above 90% of free radical scavenging) in comparison to potato-based control samples (just over 20% of free radical scavenging). The total phenolic content assay revealed the most valuable results for samples enriched with 30% chokeberry, while Ultra Performance Liquid Chromatography (UPLC) analysis allowed the determination of the most important phenolic acids. Of interest, chokeberry addition decreased the fat absorption index (FAI) after expansion by frying. Moreover, the highest values of crude protein and crude ash were observed in snack pellets supplemented by the application of 30% chokeberry. In such samples, the crude protein content was at the level of 4.75-4.87 g 100 g-1 and crude ash content at 4.88-5.07 g 100 g-1. Moreover, saturated fatty acids (SFA) content was lower in snack pellets with chokeberry addition, and increasing the amount of chokeberry additive from 10% to 30% in extruded snack pellet recipes resulted in more than double an increase in polyunsaturated fatty acids (PUFA) proportion in the total fatty acids.

A Review of the Changes Produced by Extrusion Cooking on the Bioactive Compounds from Vegetal Sources

The demand for healthy ready-to-eat foods like snacks is increasing. Physical modification of vegetal food matrices through extrusion generates significant changes in the chemical composition of the final product. There is a great variety of food matrices that can be used in extrusion, most of them being based on cereals, legumes, fruits, vegetables, or seeds. The aim of this review was to summarize the main effects of the extrusion process on the bioactive compounds content, namely phenolics, terpenes, vitamins, minerals, and fibers of vegetal mixes, as well as on their biological activity. The literature reported contradictory results regarding the changes in bioactive compounds after extrusion, mainly due to the differences in the processing conditions, chemical composition, physicochemical properties, and nutritional value of the extruded material and quantification methods. The thermolabile phenolics and vitamins were negatively affected by extrusion, while the fiber content was proved to be enhanced. Further research is needed regarding the interactions between bioactive components during extrusion, as well as a more detailed analysis of the impact of extrusion on the terpenes since there are few papers dealing with this aspect.

Degradation of polymeric polyproanthocyanidins from black chokeberry by microwave-assisted nucleophilic technique of sulfite/catechin: Reaction kinetics, antioxidation and structural analysis

Microwave was employed to enhance the degradation of polymeric proanthocyanidins from black chokeberry using the nucleophilic technique of sulfite/catechin. Based on the degradation effect and kinetics, it was found that increasing the microwave time, microwave power, microwave temperature, sulfite concentration, and mass ratio of raw material to catechins was favourable for the degradation reaction. The degradation kinetics conformed to a random first-order degradation model. The antioxidant activity of the degraded products was analysed using DPPH and O^2- assay, which suggested that the scavenging effect of the products was improved. FT-IR and ¹H NMR analyses showed that the main functional groups were not destroyed. Using MALDI-TOF/MS to study the components of the degradation products, it was found that the molecular weight distribution became narrower, and the compositions were more single. Polyproanthocyanidins were reduced to oligomers. This study suggested that microwave-assisted nucleophilic techniques could produce oligomeric proanthocyanidins with remarkably improved functionalities.

Quality Characteristics of Novel Pasta Enriched with Non-Extruded and Extruded Blackcurrant Pomace

Fruit pomace is a valuable by-product in terms of its chemical composition, which potential might be used through transformation of the pomace into food ingredients. The aim of this work was to assess the effect of partial (5% and 10%) substitution of powdered non-extruded or extruded blackcurrant pomace for semolina in pasta formula on nutritional and technological properties of the final product. The pasta was assessed for chemical composition, DPPH antiradical activity, color, cooking and textural properties. Presence of the by-products in the pasta resulted in increased total dietary fiber content (from 1.89 ± 0.06 up to 10.03 ± 0.15 g/100 g, dwb), fat content (from 1.29 ± 0.01 up to 2.70 ± 0.05 g/100 g, dwb) and DPPH antiradical activity (from 253 ± 15 up to 1037 ± 7 µmol TE/g, dwb), as well as in significantly different color (p < 0.05) as compared to the semolina-only pasta. The optimal cooking time was shortened by 1.0−1.5 min and by 2.0 min in the case of the lower and higher, respectively, level of pasta supplementation. The water absorption decreased by up to 32% in the enriched pasta. In general, the cooking loss remained unchanged. The uncooked product containing the extruded fruit pomace was characterized by significantly higher breaking strength (p < 0.05) as compared to the standard pasta. Presence of the pomace also affected texture of the cooked pasta, increasing its firmness and hardness and, when using the non-extruded pomace, the tensile strength. In our research, we have shown that durum wheat pasta enriched with 5 or 10% of powdered blackcurrant pomace or their extrudates constitute a food product of improved nutritional value and of appropriate textural characteristics, while maintaining culinary properties that meet pasta industry requirements.

The dual effect of shellac on survival of spray-dried Lactobacillus rhamnosus GG microcapsules

Heat shock and hygroscopicity are two main factors that resulted in low viability of probiotics in spray-dried microcapsules during storage. Hydrophobic polyester shellac was combined with whey protein isolate (WPI) to solve this problem. The results suggested that although the survival rate after drying decreased from 20.63% to 0.01% with increased shellac to WPI ratio, the 1:1 shellac-WPI provided the best protection among all samples during storage. The consistence between moisture-adsorption-isotherm and bacterial inactivation constants confirmed the moisture barrier effect of shellac under moderate humidity. Single-droplet drying and differential scanning calorimeter revealed that shellac addition reduced the drying rate and glass transition temperature of microcapsules, which in turn decreased the membrane integrity and growth capability of the probiotics after drying. This study revealed the dual effect of hydrophobic material on instant and long-term survival of spray-dried probiotic microcapsules, which provided new sight to the design of composite wall materials.

Effect of Addition of Chokeberry Juice Concentrate and Foaming Agent on the Physical Properties of Agar Gel

This study aimed to determine the effect of the addition of chokeberry juice concentrate (CJC) and foaming agent (egg albumin) with different percentages on the selected physical properties of agar gel. The agar gels with the addition of 5, 10, and 20% concentrations of chokeberry juice concentrate and with fructose addition were prepared. In addition, the foamed gels with different concentrations of egg albumin (in the range 0.5–2.0%) and CJC were produced. The water content, colour, density, hold-up and some mechanical and TPA (Texture Profile Analysis) descriptors as well some structural and acoustic emission parameters of non-aerated and foamed gels were analysed. The addition of CJC changed the colour of agar gel with fructose, the attractive appearance of the aerated gel was also linked with the addition of concentrate. The addition of 20% of CJC and foaming agent created samples with very low hardness, cohesiveness, and gumminess, and the structure of the aerated samples was characterised by the larger bubble diameter and the wider distribution of their size. The more promising texture and structure properties were obtained for samples with aerated gels with 5 and 10% addition of chokeberry juice concentrate.

How Do the Different Types of Carrier and Drying Techniques Affect the Changes in Physico-Chemical Properties of Powders from Chokeberry Pomace Extracts?

Chokeberry fruit, one of the richest plant sources of bioactives, is processed into different foodstuffs, mainly juice, which generates a considerable amount of by-products. To follow the latest trends in the food industry considering waste management, the study aimed to produce chokeberry pomace extract powders and conduct experimental and chemometric assessment of the effect of different carriers and drying techniques on the physico-chemical properties of such products. The PCA analysis showed that the examined powders were classified into two groups: freeze-dried (variation in case of moisture content, water activity, colour, and browning index) and vacuum-dried (bulk density). No clear pattern was observed for the physical properties of carrier added products. The sum of polyphenolics (phenolic acids, anthocyanins and flavonols) ranged from 3.3-22.7 g/100 g dry matter. Drying techniques had a stronger effect on the polyphenols profile than the type of carrier. Hydroxymethyl-L-furfural formation was enhanced by inulin addition during high-temperature treatment. Overall, the addition of maltodextrin and trehalose mixture for freeze drying and vacuum drying at 90 °C caused the highest retention of polyphenolics and the lowest formation of hydroxymethyl-L-furfural; however, an individual and comprehensive approach is required when the obtainment of high-quality chokeberry powders is expected.

Co-extruded wheat/okra composite blends result in soft, cohesive and resilient crumbs rich in health-promoting compounds

This work investigates the partial solubilization of cell wall polysaccharides in okra flours and the changes in the profile of free and bound phenolics through twin-screw extrusion. The comparison between extruded wheat flour-native okra flour (EWF-OF) and extruded wheat flour-extruded okra flour (EWF-EOF) composite blends revealed that extrusion led to an increase of soluble dietary fiber from 7.76 to 10.02 g/100 g. Extrusion of okra also resulted in a significant increase of free and bound phenolic acids, the latter consisting mostly of ferulic acid, as well as the thermal degradation of free epigallocatechin, and the binding of a small portion of quercetin-3-O-glucoside likely to a carbohydrate fraction. Bread crumbs from EWF-EOF (at 15% replacement level) exhibited a significantly lower hardness and higher elasticity, cohesiveness and resilience (from 28.28 N, 0.94, 0.49 and 0.17 to 7.54 N, 0.99, 0.70 and 0.35, respectively), which closely resembled the textural attributes of wheat bread.