Changes in functional properties and in vitro bioaccessibilities of β-carotene and lutein after extrusion processing

Starch-based composite formulation of chickpea flour and black carrot (Daucus carota l.) pomace in extruded snacks: In vitro gastrointestinal behavior and stability of bioactive compounds

Black carrot pomace (BCP) is a by-product of colorant production, containing various valuable components with the health promoting effects. In this study, for the first time, BCP was incorporated into a starch-based extruded snack formulation using wheat semolina and corn starch. Total phenolic content, total antioxidant capacity, phenolics, and anthocyanins after processing and in vitro gastrointestinal digestion were investigated, and physical and textural properties of the snack products were determined. Incorporating BCP significantly raised the TPC and antioxidant levels, notably achieving peak levels in snacks enriched with 20 % BCP. The phenolic acids and anthocyanins were increased significantly (48-382 %) (p < 0.05) with simulated gastric digestion whereas no anthocyanins were detected after simulated intestinal digestion. On the other hand, the extrusion process resulted in a negative impact on anthocyanin concentrations, particularly marked by a significant reduction in some cyanidin derivatives indicating the detrimental effect of extrusion on the molecular integrity of anthocyanins under high temperature and pressure, leading to their degradation. In the final product, the snacks displayed lower expansion indices, water absorption index, water solubility index, and lightness; but had higher hardness and redness values compared to the control and turned slightly darker. The study proposes to evaluate BCP as a value-added ingredient that imparts functional properties to foods along with the utilization of starch in the extrusion process. Additionally, the integration of wheat semolina and corn starch contributed to the structural integrity and texture of the extruded snacks, highlighting the importance of polysaccharides in the formulation.

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.

Comparative Analysis between Synthetic Vitamin E and Natural Antioxidant Sources from Tomato, Carrot and Coriander in Diets for Market-Sized Dicentrarchus labrax

Synthetic vitamin E is commonly used in aquafeeds to prevent oxidative stress in fish and delay feed and flesh oxidation during storage, but consumers’ preferences tend towards natural antioxidant sources. The potential of vegetable antioxidants-rich coproducts, dried tomato (TO), carrot (CA) and coriander (CO) was compared to that of synthetic vitamin E included in diets at either a regular (CTRL; 100 mg kg⁻¹) or reinforced dose (VITE; 500 mg kg⁻¹). Natural antioxidants were added at 2% to the CTRL. Mixes were then extruded and dried, generating five experimental diets that were fed to European sea bass juveniles (114 g) over 12 weeks. Vitamin E and carotenoid content of extruded diets showed signs of degradation. The experimental diets had very limited effects on fish growth or body composition, immunomodulatory response, muscle and liver antioxidant potential, organoleptic properties or consumer acceptance. Altogether, experimental findings suggest that neither a heightened inclusion dose of 500 mg kg⁻¹ of vitamin E, nor a 2% inclusion of natural antioxidants provided additional antioxidant protection, compared to fish fed diets including the regular dose of 100 mg kg⁻¹ of vitamin E.

Impact of tomato pomace powder added to extruded snacks on the in vitro gastrointestinal behaviour and stability of bioactive compounds

In this study, extruded snacks enriched with tomato pomace powder (TPP) at ratios of 5, 10, 15, and 20% (w/w) were prepared based on some preliminary experiments. The effect of tomato pomace addition to extruded snacks on the total phenolic content, total antioxidant capacity, contents of lycopene and phenolics, as well as their in vitro bioaccessibility; and additionally, physical, textural and sensory properties of the samples were investigated. According to the results, increasing levels of TPP in snacks significantly increased the content of individual phenolics including gallic acid, protocatechuic acid, 2,5-dihydroxybenzoic acid, chlorogenic acid, rutin and quercetin. Similarly, increased amount of TPP in snacks enhanced the bioaccessible protocatechuic acid, chlorogenic acid, rutin and quercetin as well as lycopene (p < 0.05). TPP incorporated snacks displayed lower expansion indices, water absorption index (WAI) and water solubility index (WSI) and lightness; but had higher hardness, redness and yellowness values than the control. However, snacks had acceptable physical and sensory properties when enriched with 10% of TPP. The results suggest that tomato pomace can be added as a functional ingredient to improve the nutritional value of snack products.

High-Pressure Processing of Kale: Effects on the Extractability, In Vitro Bioaccessibility of Carotenoids & Vitamin E and the Lipophilic Antioxidant Capacity

High pressure processing (HPP) represents a non-thermal preservation technique for the gentle treatment of food products. Information about the impact of HPP on lipophilic food ingredients (e.g., carotenoids, vitamin E) is still limited in more complex matrices such as kale. Both the variation of pressure levels (200–600 MPa) and different holding times (5–40 min) served as HPP parameters. Whereas a slightly decreasing solvent extractability mostly correlated with increasing pressure regimes; the extension of holding times resulted in elevated extract concentrations, particularly at high-pressures up to 600 MPa. Surprisingly, slightly increasing bioaccessibility correlated with both elevated pressures and extended holding times, indicating matrix-dependent processes during in vitro digestion, compared to results of extractability. Moreover, the verification of syringe filters for digest filtration resulted in the highest relative recoveries using cellulose acetate and polyvinylidene difluoride membranes. The α-tocopherol equivalent antioxidant capacity (αTEAC) and oxygen radical antioxidant capacity (ORAC) assays of treated kale samples, chopped larger in size, showed increased antioxidant capacities, regarding elevated pressures and extended holding times. Consequently, one may conclude that HPP was confirmed as a gentle treatment technique for lipophilic micronutrients in kale. Nevertheless, it was indicated that sample pre-treatments could affect HP-related processes in food matrices prior to and possibly after HPP.

Changes in Phenolics during Cooking Extrusion: A Review

In this paper, significant attention is paid to the retention of phenolics in extrudates and their health effects. Due to the large number of recent articles devoted to total phenolic content (TPC) of input mixtures and extrudates, the technological changes are only presented for basic raw materials and the originating extrudates, and only the composites identified has having the highest amounts of TPC are referred to. The paper is also devoted to the changes in individual phenolics during extrusion (phenolic acids, flavonoids, flavonols, proanthocyanidins, flavanones, flavones, isoflavons, and 3-deoxyanthocyanidins). These changes are related to the choice or raw materials, the configuration of the extruder, and the setting the technological parameters. The results found in this study, presented in the form of tables, also indicate whether a single-screw or twin-screw extruder was used for the experiments. To design an extrusion process, other physico-chemical changes in the input material must also be taken into account, such as gelatinization of starch; denaturation of protein and formation of starch, lipids, and protein complexes; formation of soluble dietary fiber; destruction of antinutritional factors and contaminating microorganisms; and lipid oxidation reduction. The chemical changes also include starch depolymerization, the Maillard reaction, and decomposition of vitamins.

Physical Characterization of Maize Grits Expanded Snacks and Changes in the Carotenoid Profile

The objective of this work was to evaluate the effects of feed moisture (13-17%, wb) and barrel temperature (120-160 °C) on physicochemical properties, and changes in the carotenoid profile of maize grits extruded snacks. The extrudates were obtained in a single-screw extruder, according to a 3² factorial design with two replicates. The linear coefficients of feed moisture and barrel temperature mainly affected the physicochemical properties. On the other hand, the interaction coefficient β₁₁₂ dominated the change in total carotenoids, lutein, zeaxanthin, and β-carotene. The quadratic coefficients were also important for changes in total color (regarding feed moisture), and for β-cryptoxanthin, specific mechanical energy, and volumetric expansion index (regarding barrel temperature). β-cryptoxanthin and β-carotene increased, whereas lutein and zeaxanthin decreased. The mathematical models developed from responses revealed two feasible operating regions under the domain explored. For a satisfactory process, from a technological and nutritional point of view, it is suggested to extrude at the operating conditions ranging between 13.2-13.7% feed moisture and 120-132 °C barrel temperature. Under these conditions, the specific mechanical energy input required was 410-450 kJ/kg, and extrudates with a volumetric expansion index greater than 12, a crispness work less than 0.4 N.mm, and with moderate increments in the levels of β-carotene and β-cryptoxanthin were produced. The use of richer cultivars in carotenoids could contribute to the production of healthier snacks.

Effects of processing on onion skin powder added extrudates

It is possible to enhance the functional properties of extruded products with the inclusion of fruit and vegetable by-products. Onion skin, a rich source of quercetin and fiber, is considered as waste in the industry and can be used as an alternative ingredient to improve the nutritional value of the extruded products. Three levels (3, 6, and 9%) of onion skin powder (OSP) were added to wheat flour and compared with control (0% OSP). The effect of the extrusion process on accessible quercetin, total phenolic content, and antioxidant activity of the samples were investigated. In addition, carbohydrate digestibility analyses were conducted for the products. Mass spectrometry (LC-MS/MS) results indicated that increasing the OSP level increased the quercetin content. The process caused the release of the entrapped quercetin from OSP, which was revealed by significantly higher quercetin levels for the extrudates. Some of the quercetin was lost during in vitro digestion process. Increasing the OSP level increased antioxidant activity and total phenolic contents of the samples. Total phenolic contents decreased significantly after the processing, yet antioxidant activities were not affected. The extruded products showed high amounts of rapidly available glucose (69.5 g/100 g). The OSP enhancement did not change the carbohydrate digestibility of products. The results indicated that the extrusion process could increase the level of accessible bioactive ingredients, and the level of functional compound addition can be optimized further.

Carotenoid content of extruded and puffed products made of colored-grain wheats

Wheat is a relevant source not only of essential macronutrients but also of many other health-promoting phytochemicals (carotenoids, anthocyanins, tocols, phenolic acids, etc.). Colored-grain wheats were used for extrusion and kernel puffing. The total content of carotenoids (sum of lutein, zeaxanthin, antheraxanthin, α- and β-carotene, and xanthophyll esters) decreased significantly due to extrusion (to 25.7%) and puffing (to 31.6%), compared to the content in the raw material. Zeaxanthin was shown to be the most stable among all detected carotenoids (30.8 and 48.7% was preserved). The results of the performed analyses have not confirmed greater stability of xanthophyll esters against higher temperatures (decrease to 29.5 and 22.1%). Both technologies induced E-to Z-isomerization of all-E-lutein and puffing also of all-E-zeaxanthin. Higher concentrations of 13-Z- and 9-Z-zeaxanthin were identified in puffed grains (2× and 37× on average). To preserve more carotenoids, it is appropriate to look for a more suitable food processing technology.