In Vitro Bioaccessibility of Bioactive Compounds from Citrus Pomaces and Orange Pomace Biscuits

The present investigation aimed to provide novel information on the chemical composition and in vitro bioaccessibility of bioactive compounds from raw citrus pomaces (mandarin varieties Clemenule and Ortanique and orange varieties Navel and Valencia). The effects of the baking process on their bioaccessibility was also assessed. Samples of pomaces and biscuits containing them as an ingredient were digested, mimicking the human enzymatic oral gastrointestinal digestion process, and the composition of the digests were analyzed. UHPLC-MS/MS results of the citrus pomaces flavonoid composition showed nobiletin, hesperidin/neohesperidin, tangeretin, heptamethoxyflavone, tetramethylscutellarein, and naringin/narirutin. The analysis of the digests indicated the bioaccessibility of compounds possessing antioxidant [6.6–11.0 mg GAE/g digest, 65.5–97.1 µmol Trolox Equivalents (TE)/g digest, and 135.5–214.8 µmol TE/g digest for total phenol content (TPC), ABTS, and ORAC-FL methods, respectively; significant reduction (p < 0.05) in Reactive Oxygen Species (ROS) formation under tert-butyl hydroperoxide (1 mM)-induced conditions in IEC-6 and CCD-18Co cells when pre-treated with concentrations 5–25 µg/mL of the digests], anti-inflammatory [significant reduction (p < 0.05) in nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW264.7 macrophages], and antidiabetic (IC50 3.97–11.42 mg/mL and 58.04–105.68 mg/mL for α-glucosidase and α-amylase inhibition capacities) properties in the citrus pomaces under study. In addition, orange pomace biscuits with the nutrition claims “no-added sugars” and “source of fiber”, as well as those with good sensory quality (6.9–6.7, scale 1–9) and potential health promoting properties, were obtained. In conclusion, the results supported the feasibility of citrus pomace as a natural sustainable source of health-promoting compounds such as flavonoids. Unfractionated orange pomace may be employed as a functional food ingredient for reducing the risk of pathophysiological processes linked to oxidative stress, inflammation, and carbohydrate metabolism, such as diabetes, among others.

Resíduos da laranja na elaboração de produtos alimentícios: Uma revisão

O objetivo deste estudo foi compilar e analisar publicações entre os anos 2010 e 2020 que utilizaram resíduos da laranja na elaboração de produtos alimentícios. A revisão bibliográfica de literatura foi do tipo sistemática, aplicando os termos: “orange by-products”, “orange peel flour”, “orange albedo flour”, “orange peel fiber”, “orange pomace flour” e suas combinações nas línguas portuguesa e inglesa, nas bases de dados Google Acadêmico, SciELO e Periódicos CAPES. Os critérios de inclusão compreenderam o desenvolvimento de produtos alimentícios com incorporação de resíduos da laranja, a caracterização físico-química e/ou centesimal, sensorial, entre outras. Definiu-se três filtros de seleção para análise: título e palavras-chave, resumo e metodologia, e leitura. Foram encontrados 468 estudos, sendo 22 o número de artigos que atenderam os critérios de seleção para a coleta e análise dos dados. Observou-se que as pesquisas são relevantes e variadas, muitos produtos já foram elaborados com resíduos da laranja: pães, bolos, biscoitos, massa, geleia, sorvetes, hambúrguer e cerveja. O aproveitamento dos resíduos da laranja originou subprodutos com melhoria nas características físico-químicas, microbiológicas, sensoriais, capacidade antioxidante e compostos bioativos. Considera-se que a utilização de resíduos da laranja é uma alternativa viável para elaboração de produtos alimentícios, com potencial de comercialização, garantindo a valorização da cultura e a redução do desperdício.

Evaluation of nutritional characteristics and consumers’ acceptance of gluten-free sweet biscuits made from rice-based pregelatinized composite flours containing orange pomace and soy protein isolate

Gluten-free bakery products are usually deficient in dietary fiber and inferior sources of protein. Studies that have assessed sensory characterization of products prepared with orange pomace are scarce. This study evaluated the employment of 30% of rice-based pregelatinized composite flours (containing 15, 25 or 35% orange pomace blended with 5% soy protein isolate) on gluten-free biscuits. The target was the investigation of the nutritional profile and consumer’s acceptance of three short dough sweet biscuit samples. Thermoplastic extrusion was an efficient unit operation for the elaboration of a new gluten-free ingredient in which a by-product rich in total dietary fiber and a component with a high level of protein were employed. All pregelatinized composite flours in this study can be labeled as protein sources and can be claimed as high in total dietary fiber content, as well as two biscuit samples that can be labeled as total dietary fiber source. Also, all pregelatinized composite flours and biscuits presented low moisture and water activity, being microbiologically stable to room temperature (25 ± 2 °C). Complementarily, the results of the microbiological evaluations [(coagulase-positive Staphylococcus, thermotolerant coliform (45 °C) and Salmonella sp. (absence in 25 g)] of the biscuits and their comparison with the Brazilian microbiological standards legislation attested their safety. Concerning the sensory analysis, adults’ results showed that the flavor attribute might be responsible for increasing the overall impression score of a sample. In contrast, children’s results showed that they did not distinguish (p ≥ 0.05) two of three samples of biscuits analyzed.

Optimization of Vacuum-Microwave-Assisted Extraction of Natural Polyphenols and Flavonoids from Raw Solid Waste of the Orange Juice Producing Industry at Industrial Scale

Orange pomace (OP) is a solid waste produced in bulk as a byproduct of the orange juice industry and accounts for approximately 50% of the quantity of the fruits processed into juice. In numerous literature references there is information about diverse uses of orange pomace for the production of high-added-value products including production of natural antioxidant and antimicrobial extracts rich in polyphenols and flavonoids which can substitute the hazardous chemical antioxidants/antimicrobials used in agro-food and cosmetics sectors. In this work and for the first time, according to our knowledge, the eco-friendly aqueous vacuum microwave assisted extraction of orange pomace was investigated and optimized at real industrial scale in order to produce aqueous antioxidant/antimicrobial extracts. A Response Surface Optimization methodology with a multipoint historical data experimental design was employed to obtain the optimal values of the process parameters in order to achieve the maximum rates of extraction of OP total polyphenols and/or total flavonoids for economically optimum production at industrial scale. The three factors used for the optimization were: (a) microwave power (b) water to raw pomace ratio and (c) extraction time. Moreover, the effectiveness and statistical soundness of the derived cubic polynomial predictive models were verified by ANOVA.