Bioactive compounds from orange epicarp to enrich fish burgers

The potential of citrus by-products in the development of functional food and active packaging

Food by-product valorization has become an important research area for promoting the sustainability of the food chain. Citrus fruits are among the most widely cultivated fruit crops worldwide. Citrus by-products, including pomace, seeds, and peels (flavedo and albedo), are produced in large amounts each year. Those by-products have an important economic value due to the high content on bioactive compounds, namely phenolic compounds and carotenoids, and are considered a valuable bio-resource for potential applications in the food industry. However, green extraction techniques are required to ensure their sustainability. This chapter addresses the main components of citrus by-products and their recent applications in food products and active food packaging, towards a circular economy. In addition, the concern regarding citrus by-products contamination (e.g. with pesticides residues and mycotoxins) is also discussed.

Citrus By-Products: Valuable Source of Bioactive Compounds for Food Applications

Citrus production produces about 15 million tons of by-products/waste worldwide every year. Due to their high content of bioactive compounds, several extraction techniques can be applied to obtain extracts rich in valuable compounds and further application into food applications. Distillation and solvent extraction continues to be the most used and applied extraction techniques, followed by newer techniques such as microwave-assisted extraction and pulsed electric field extraction. Although the composition of these extracts and essential oils directly depends on the edaphoclimatic conditions to which the fruit/plant was exposed, the main active compounds are D-limonene, carotenoids, and carbohydrates. Pectin, one of the most abundant carbohydrates present in Citrus peels, can be used as a biodegradable polymer to develop new food packaging, and the extracted bioactive compounds can be easily added directly or indirectly to foods to increase their shelf-life. One of the applications is their incorporation in active food packaging for microbiological and/or oxidation inhibition, prolonging foods' shelf-life and, consequently, contributing to reducing food spoilage. This review highlights some of the most used and effective extraction techniques and the application of the obtained essential oils and extracts directly or indirectly (through active packaging) to foods.

Citrus Peel Flavonoid Extracts: Health-Beneficial Bioactivities and Regulation of Intestinal Microecology in vitro

Citrus peel and its extracts are rich in flavonoids, which are beneficial to human health. In this study, the extraction, component analysis, biological activity and intestinal microbiota regulation of citrus peel flavonoid extracts (CPFEs) were investigated. CPFEs from 14 Chinese cultivars were purified by ultrasound-assisted extraction and XAD-16 macroporous resin. The total flavonoid content of lemon was greatest at 103.48 ± 0.68 mg/g dry weight (DW) by NaNO2-Al(NO3)3-NaOH spectrophotometry. Using high-performance liquid chromatography–diode array detection, the highest concentrations of naringin, hesperidin and eriocitrin were found in grapefruit (52.03 ± 0.51 mg/g DW), chachiensis (43.02 ± 0.37 mg/g DW) and lemon (27.72 ± 0.47 mg/g DW), respectively. Nobiletin was the most polymethoxylflavone in chachiensis at 16.91 ± 0.14 mg/g DW. CPFEs from chachiensis and grapefruit had better antioxidant activity, α-glucosidase inhibitory and sodium glycocholate binding ability. In addition, chachiensis and grapefruit CPFEs had positive effects on intestinal microecology, as evidenced by a significant increase in the relative abundance of Bifidobacterium spp., and production of short-chain fatty acids, especially acetic acid, by a simulated human intestinal model. Collectively, our results highlight the biological function of CPFEs as prebiotic agents, indicating their potential use in food and biomedical applications.

Effect of an Emulsified Formulation on Vegetable Carotenoid Bioaccessibility

We investigated the effect of neutral lipids, polar lipids, and an emulsified formulation (EMF) on carotenoid bioaccessibility in an in vitro digestion assay of vegetables. These reagents enhanced carotenoid bioaccessibility. Contrary to our previous report, they also exhibited effects on lutein. Bile extracts/pancreatin concentrations also participated in the bioaccessibility. The EMF, which consisted of lower amounts of oil, had the same effect on lutein as rapeseed oil. These reagents also showed effects in the aging model, with more reduced bile extract/pancreatin concentrations, suggesting that lipids and EMF contributed to carotenoid bioaccessibility in bile/pancreatic juice secretions due to aging and disease.

Sweet and bitter oranges: An updated comparative review of their bioactives, nutrition, food quality, therapeutic merits and biowaste valorization practices

Sweet and bitter oranges are two of the most commercially-important fruit with a total world production of 75.4 Mt, well-recognized for their unique sensory characters in addition to multiple nutritive and therapeutic attributes due to their highly-valued bioactive ingredients. Hence, their differential qualitative/quantitative phytochemical make-ups are presented for better utilization as therapeutic agents. Sweet orange exhibits therapeutic applications as being effective anti-diabetic, anti-obesity, and hypocholesterolemic agents. Whereas, for anti-osteoporotic products and intestinal dysbiosis treatment, bitter orange is more preferred. Moreover, the review recapitulates on different valorization practices of citrus bio-wastes and utilization of their bioactives as therapeutic agents and in functional food industry. Sweet orange waste functions as a fat replacer and preservative to increase food shelf life with better organoleptic attributes than bitter orange. The detailed action mechanism and safety of Citrus bioactives, as well as processing technologies to further improve its effects are posed as future research perspectives.

Quality Characteristics and Functional and Antioxidant Capacities of Algae-Fortified Fish Burgers Prepared from Common Barbel (Barbus barbus)

INTRODUCTION

Algae have been used as natural ingredients to produce new canned fish burgers prepared from minced flesh of common barbel. In this research, the impact of the addition of Cystoseira compressa and Jania adhaerens at concentrations of 0.5, 1, and 1.5% w/v on the texture and sensory characteristics of fish burgers were investigated.

RESULTS

Compared to controls, fish burgers containing 1% algae had better texture and sensory properties (P < 0.05). Also, these burger formulations had higher water and oil holding capacities as well as swelling ability, due to the important polysaccharides and dietary fibers contents of algae. In addition, algae-supplemented burgers were characterized as having low L⁎, a⁎, and b⁎ values, which made the color appear to be paler. Thanks to their high richness in pigments (chlorophylls and carotenoids) and polysaccharides, algae considerably enhance the antioxidant activities of the new ready-to-eat fish burgers. So, Cystoseira compressa and Jania adhaerens could be used as nutritious additives to produce new fish-based products.

Development of Health Products from Natural Sources

BioActive Compounds (BACs) recovered from food or food by-product matrices are useful in maintaining well being, enhancing human health, and modulating immune function to prevent or to treat chronic diseases. They are also generally seen by final consumers as safe, non-toxic and environment-friendly. Despite the complex process of production, chemical characterization, and assessment of health effects, BACs must also be manufactured in stable and bioactive ingredients to be used in pharmaceutical, food and nutraceutical industry. Generally, vegetable derivatives occur as sticky raw materials with pervasive smell and displeasing flavor. Also, they show critical water solubility and dramatic stability behavior over time, involving practical difficulties for industrial use. Therefore, the development of novel functional health products from natural sources requires the design of a suitable formulation to delivery BACs at the site of action, preserve stability during processing and storage, slow down the degradation processes, mask lousy tasting or smell, and increase the bioavailability, while maintaining the BACs functionality. The present review focuses on human health benefits, BACs composition, and innovative technologies or formulation approaches of natural ingredients from some selected foods and by-products from industrial food transformations.

Comparative Study of Orange and its Main Bioactive Constituents as Remedy for Non-alcoholic Fatty Liver in Rats

BACKGROUND AND OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is accused as inducer of both cardiovascular and chronic liver diseases. The aim of the present study was to evaluate the therapeutic effect of combined freeze dried orange juice with its dried pulp supplemented with methionine, as functional food, in comparison to orange bioactive constituents, as parallel formula, in NAFLD rat model.

MATERIALS AND METHODS

Proximate composition, dietary fibers, minerals, total phenolics, fatty acids and phytosterols were determined in the orange functional food. The NAFLD was induced in rats through feeding high fructose diet. The prepared functional food and its parallel formula were evaluated in NAFLD rats through determination of liver fat and plasma lipid profile, malondialdehyde, tumor necrosis factor-α, leptin, insulin and glucose as well as liver and kidney function with histopathological examination of the liver. Insulin resistance (IR) and total cholesterol/high density lipoprotein cholesterol were calculated.

RESULTS

Orange functional food was shown to contain 9.17% dietary fibers, 1.4% potassium, 1.4 phenolic content as mg gallic acid/g, oleic acid as the major fatty acid (29.75% of total fatty acids) and 11.97% phytosterols from unsaponifiable matter. The studied formulas produced reduction of liver and plasma lipids, inflammatory and oxidative stress biomarkers, IR and leptin with improving liver function and histopathology pointing to potential management of NAFLD.

CONCLUSION

Orange functional food and its parallel formula were promising in management of NAFLD; with superiority to orange functional food. Phenolic compounds, dietary fibers, phytosterols and mono and poly-unsaturated fatty acids could be responsible to the bioactivity of orange formula.