Upcycling fruit pomaces (orange, apple, and grape-wine): The impact of particle size on phenolic compounds' bioaccessibility.

This work aimed to analyse the effect of particle size on bioactive compounds of different by-products. Orange, apple, and grape-wine by-products obtained from industrial production were dried and ground at two sizes: 1 mm and 0.5 mm. Pomaces were analysed in composition (protein, fat, carbohydrates, moisture, and ash contents) and bioactive compounds (total phenol content by Folin- Ciocalteu method and antioxidant capacity by FRAP assay) and submitted to an in-vitro digestion. FESEM was used to observe the microstructure of samples. All pomaces showed high fibre content (21.7, 31.2, and 58.9 g/100 g, in apple, orange, and grape pomace respectively). Total phenol content in raw material was higher in grape > orange > apple, with no differences (apple) or slight differences (grape and orange) between 1 mm and 0.5 mm particle size. Grape pomace was observed as a porous, more accessible structure, where extracting polyphenols was easier. Orange pomace', was compact and apple pomace structure was even more compact hindering the raw materials polyphenol extraction. After digestion, total phenol content increased in orange and apple pomace for both particle size. In apple, bioaccessibility of phenolic compounds showed a 5 fold increase for 1 mm sample size and a 4 fold increase for 0.5 mm sample size. In orange, for both sizes bioaccessibility increased but to a lesser extent (2.4 fold). In the case of grape pomace, although polyphenol content decreased after digestion (0.7 fold for both sizes), they showed the highest antioxidant capacity. Regarding the effect of particle size on total polyphenol content and antioxidant capacity, no trend was found in this work for the fruit pomaces studied. In the case of grape and apple, grinding at 1 mm should be adequate regarding antioxidant capacity while in the case of orange, it may be better to use a pomace ground at 0.5 mm.

Assessment of in vitro digestion of reduced sugar biscuits with extruded brewers' spent grain.

This study aimed to evaluate the nutritional value and potential health claims for reduced sugar biscuits containing extruded brewers' spent grain (EBSG) and fructooligosaccharides (FOS). One traditional biscuit with added sugar and three reduced sugar biscuits containing 15.2 % FOS and EBSG (0, 8 and 17 %), with nutrition claims "high in fiber" and "source of protein" for those containing 17 % of EBSG, were formulated. Biscuits were characterized by analysis of nutrients and bioactive compounds before and after digestion under in vitro enzymatic oral-gastro-intestinal and colonic fermenting conditions. The bioaccessibility of antioxidants, anti-inflammatory and antidiabetic compounds in biscuits' intestinal digests and short-chain fatty acids in colonic samples was analyzed. EBSG-added biscuits showed significantly lower (p < 0.05) glucose intestinal bioaccessibility and significantly higher (p < 0.05) phenolic compounds intestinal bioaccessibility compared to biscuits without EBSG. EBSG-added biscuits showed significantly (p < 0.05) higher in vitro antidiabetic potential than the other did. Moreover, the intestinal digest of biscuits containing 17 % EBSG exhibited significantly (p < 0.05) better in vitro inhibition of intracellular ROS formation and in vitro anti-inflammatory properties. FOS addition (p < 0.05) significantly improved the production of butyric acid while EBSG did for valeric acid which possess chemoprotective effect. In conclusion, the combined use of FOS (15.2 %) and EBSG (17 %) allowed obtaining a human healthier snack formulation for satisfying consumers' demands and achieving nutrition security.

Incorporating an upcycled orange fibre on flan formulation: Impact on sensory properties.

Fruit by-products are a valuable source of ingredients, in the formulation of what is known by "upcycled foods". Orange pomace, a by-product of orange juice industry, is a dietary fibre source. In this work, a powdered ingredient with soluble fibre obtained from orange pomace was used as replacement of inulin in the formulation of source of fibre "flan" like puddings. Four different formulations were analysed using Flash Profile and instrumental texture: 100% inulin, 70% inulin: 30% orange fibre, 30% inulin: 70% orange fibre, 100% orange fibre. The replacement of 30% of pudding's total fibre with the new ingredient helped to improve the texture and general appearance of the dessert. Greater percentages imparted non-desirable flavour attributes, such as bitterness and acidity. The use of this ingredient as a replacement of commercial inulin in the formulation of source of fibre puddings is possible. However, further research is needed to reduce the off flavours.

Sorption Isotherms, Glass Transition and Bioactive Compounds of Ingredients Enriched with Soluble Fibre from Orange Pomace.

Citrus fruits are one of the main crops worldwide. Its industrialization, primarily juice production, produces large amounts of byproducts, composed of seeds and peels, that can be used to obtain new ingredients. In this study, sorption behaviour, glass transition, mechanical properties, colour and bioactives of four different soluble fibre-enriched powders obtained from orange pomace using green technologies were studied. Powders were equilibrated at water activities between 0.113 and 0.680 for fifteen weeks at 20 °C, and studies were performed to indicate the best storing conditions to ensure the glassy state of the amorphous matrix and higher bioactive stability. By combining the Gordon and Taylor model with the Henderson isotherm, the critical water activity and content for storage in a glassy state were determined. The ingredient obtained after extrusion + hot water is the most stable, which is also the one with the highest dietary fibre content. Powder obtained by jet cooking is the least stable, as it is not in a glassy state at any water activity at room temperature. To increase storage stability, these should be stored at refrigeration temperatures.

In Vitro Digestibility and Bioaccessibility of Nutrients and Non-Nutrients Composing Extruded Brewers' Spent Grain.

This study aimed to evaluate the effect of the extrusion process on the bioaccessibility of brewers' spent grain (BSG) nutrients (carbohydrates and proteins) and non-nutrients (bioactive compounds). BSG and extruded BSG (EBSG) were digested in vitro simulating human oral-gastro-intestinal digestion and colonic fermentation. The duodenal bioaccessibility of glucose, amino acids and phenolic compounds was analyzed. The fermentability of the dietary fiber was assessed by analysis of short-chain fatty acids. Additionally, assessment of the bioaccessibility of phenolic compounds after colonic fermentation was undertaken. The antioxidant, anti-inflammatory and antidiabetic properties of the bioaccessible compounds were studied. Extrusion caused no change in the digestibility of gluten and glucose bioaccessibility (p > 0.05). Moreover, the bioaccessibility of amino acids and phenolic compounds significantly increased (p < 0.05) due to extrusion. However, higher short-chain fatty acid content was formed in colonic fermentation of BSG (p < 0.05) compared to EBSG. The latter inhibited intracellular ROS formation in IEC-6 cells and showed anti-inflammatory properties in RAW264.7 cells. With respect to antidiabetic properties, glucose absorption was lower, and the inhibition of carbohydrases higher (p < 0.05), in the presence of EBSG compared to BSG. The effects of EBSG and BSG digests on glucose transporters were not significantly different (p > 0.05). In conclusion, extrusion positively affected the nutritional value and health-promoting properties of BSG.

Feasibility of Extruded Brewer's Spent Grain as a Food Ingredient for a Healthy, Safe, and Sustainable Human Diet.

This study aimed to determine the effect of the extrusion process on the nutritional and bioactive profiles of brewer's spent grain (BSG), contributing to nutrition security by applying a circular economy concept. Response surface methodology was used to optimize the effect extrusion parameters (moisture content, screw speed, and barrel temperature ) had on BSG's soluble dietary fiber, free glucose, and overall antioxidant capacity. Proximate composition analyses, amino acid profile, extractable polyphenolic content, and antioxidant capacity of BSG and brewer's spent grain extruded under optimal conditions (BSGE) were carried out. Food safety was analyzed by their microbiological quality, gluten, and acrylamide content. Optimal extrusion conditions were 15.8% of moisture content, 164.3 revolutions per min and 122.5 °C. BSGE presented 61% more soluble dietary fiber than BSG, lower digestible starch, 0.546% of free glucose, and protein quality parameters mostly like those reported for egg, soy, and milk. Despite this, BSG's overall antioxidant capacity was not improved after thermomechanical processing; BSGE had significantly higher extractable polyphenolic content in its alkali extracts, which were determined qualitatively by high-performance liquid chromatography quadrupole time-of-flight assay in its hydro-alcoholic acid extracts. Furthermore, although it is not gluten free, BSGE is a safe food ingredient with acceptable microbiological quality and no acrylamide.

Consumer Response to Cake with Apple Pomace as a Sustainable Source of Fibre.

The use of apple pomace flour (APF) as a fibre enrichment strategy was investigated. The aim of this study was to evaluate consumers' response to intrinsic and extrinsic properties of a bakery premix product when using APF. Apple pomace, a by-product from the juice industry, was dried and ground. APF is high in carbohydrates (47.47%) and fibre (38.48%), and it was used to partially substitute wheat flour and sugar in a cake premix. Acceptability, health, and nutrition questions were evaluated with and without information in terms of regular and fibre-enriched cake. The regular cake score was not affected by information, while the enriched cake's score increased with information. Three clusters were identified. Cluster 1 (29%) showed high liking scores for regular cake, cluster 2 (31%) for the fibre-enriched cake, and cluster 3 (40%) showed similar liking for both. Consumers described the samples and ideal cake using a check-all-that-apply (CATA) questionnaire. Penalty analyses explained differences in acceptability among consumers. Healthiness, tastiness, and fibre content were the main reasons to buy the enriched cake for cluster 2; taste for consumers in cluster 1; and healthiness and taste for consumers in cluster 3. APF as a functional ingredient may be a consumers' choice as a sustainable use of apple pomace.

Sensory Features Introduced by Brewery Spent Grain with Impact on Consumers' Motivations and Emotions for Fibre-Enriched Products.

The aim of this work was both to formulate three different fibre-enriched products by the addition of Brewery Spent Grain (BSG), and to evaluate the impact of this fibre enrichment on sensory quality, acceptability, and purchase intention under blind conditions. BSG was incorporated into bread, pasta, and chocolate milk at levels of 8.3%, 2.8%, and 0.35% (w/w), respectively. The fibre-enriched products and their regular counterparts were evaluated together by consumers through a CATA questionnaire, the EsSense 25 Profile, an overall acceptability rating, and a purchase intention ranking. Although fibre-enriched bread and chocolate milk ranked lower in overall acceptability compared with their counterparts, no significant difference was found for fibre-enriched pasta (p > 0.05). Purchase intention did not differ significantly for both bread and pasta (p > 0.05), yet the reasons for purchasing them differed significantly (p < 0.05). Consumers recognised the fibre enrichment in these two products and, therefore, were willing to partially compromise on sensory attributes. The fibre-enriched chocolate milk, nonetheless, scored significantly (p < 0.05) lower in purchase intention than the control. This work demonstrates that the effect of BSG addition is product-specific, and that fibre perception makes consumers feel more confident.

Blueberry pomace as a source of antioxidant fibre in cookies: Consumer's expectations and critical attributes for developing a new product.

Valorisation of an agroindustry by-product, through its uses as an ingredient, in the development of a product may be an opportunity for industries to reduce wastes; generating a valuable product rich in bioactive compounds. Nevertheless, as happens with every new product, food manufacturers follow the market trend ensuring that any new product or idea meets consumer's expectations. The aim of this work is to study the expectation and the acceptability of consumers towards fibre-enriched cookies using blueberry pomace as a functional ingredient. A label for the blueberry cookies, created for this purpose, was evaluated by consumers who rated their expected liking when observing this label. Fibre-enriched cookies were formulated using blueberry pomace powder as source ingredient for antioxidant dietary fibre. A cookie without fibre was evaluated as a reference. Cookies were evaluated by a group of consumers who rated their degree of liking when tasting the sample under blind and informed conditions. Results showed that the consumer expectations were not fulfilled when assessing the product. Acceptability scores of blueberry pomace, fibre-enriched cookies show that most consumers are not willing to compromise hedonic aspects of cookies for their healthful attributes. Focus group was used to explore the characteristics a healthy cookie should have. Formulation of cookies must be optimised taking into account the acceptability of consumers.

Blueberry by-product used as an ingredient in the development of functional cookies.

A by-product of blueberry juice industries was used as an ingredient to develop fiber-enriched cookies. The blueberry pomace, once ground and dried, was used as an ingredient in cookie formulation. A control cookie was elaborated as reference. Cookies were analyzed for composition and functional properties. The fiber content obtained in the fiber-enriched cookie allows it to be labeled as "high fiber" in the European Union and as a "source of fiber" in MERCOSUR. The fiber-enriched cookie presented highly increased values on the antioxidant capacity and the polyphenol content when compared against the control cookie. Sensory evaluation was performed. Acceptability of the fiber-enriched cookie reached a value of 5.3 in a nine-point hedonic scale. Further strategies should be necessary in order to achieve an acceptable product. Cookies were subjected to an in vitro digestive process. Results show that the cookies' phytochemicals are bioaccessible and potentially bioavailable. Therefore, eating this type of food would represent an increase in the amount of antioxidants ingested and redound to a health benefit. In addition to improving both nutritional and functional properties of cookies, the present development represents an innovative strategy for a more sustainable growth of fruit juice industries.