Eggplant Fruit (Solanum melongena L.) and Bio-Residues as a Source of Nutrients, Bioactive Compounds, and Food Colorants, Using Innovative Food Technologies

Analytical Strategies for Green Extraction, Characterization, and Bioactive Evaluation of Polyphenols, Tocopherols, Carotenoids, and Fatty Acids in Agri-Food Bio-Residues

Recent advancements in analytical strategies have enabled the efficient extraction and characterization of bioactive compounds from agri-food bio-residues, emphasizing green chemistry and circular economy principles. This review highlights the valorization of several agri-food bio-residues for the extraction of high-value-added bioactive compounds, particularly polyphenols, tocopherols, carotenoids, and fatty acids, as a biorefinery approach. To this end, the adoption of environmentally friendly extraction technologies is essential to improve performance, reduce energy consumption, and minimize costs. This study therefore examines emerging methodologies such as supercritical fluid extraction, pressurized liquid extraction, pulsed electric fields, and matrix solid-phase dispersion, highlighting their advantages and limitations. Additionally, the chemical characterization of these bioactive compounds is explored through spectrophotometric and high-resolution chromatographic techniques, crucial for their accurate identification and quantification. This is complemented by an analysis of bioactivity assays evaluating antioxidant, antimicrobial, anticancer, neuroprotective, and anti-inflammatory properties, with a focus on their applications in the food, pharmaceutical, and cosmetic industries. However, the analytical control of toxic compounds, such as alkaloids, in these bio-residues is undoubtedly needed. Ultimately, this approach not only promotes sustainability but also contributes to the development of eco-friendly solutions in various industries.

Genetic and Biotechnological Approaches to Improve Fruit Bioactive Content: A Focus on Eggplant and Tomato Anthocyanins

Anthocyanins are a large group of water-soluble flavonoid pigments. These specialized metabolites are ubiquitous in the plant kingdom and play an essential role not only in plant reproduction and dispersal but also in responses to biotic and abiotic stresses. Anthocyanins are recognized as important health-promoting and chronic-disease-preventing components in the human diet. Therefore, interest in developing food crops with improved levels and compositions of these important nutraceuticals is growing. This review focuses on work conducted to elucidate the genetic control of the anthocyanin pathway and modulate anthocyanin content in eggplant (Solanum melongena L.) and tomato (Solanum lycopersicum L.), two solanaceous fruit vegetables of worldwide relevance. While anthocyanin levels in eggplant fruit have always been an important quality trait, anthocyanin-based, purple-fruited tomato cultivars are currently a novelty. As detailed in this review, this difference in the anthocyanin content of the cultivated germplasm has largely influenced genetic studies as well as breeding and transgenic approaches to improve the anthocyanin content/profile of these two important solanaceous crops. The information provided should be of help to researchers and breeders in devising strategies to address the increasing consumer demand for nutraceutical foods.

Ultrasound-Assisted Extraction of Bioactive Compounds from Broccoli By-Products

The objective of this work was to gain insight into the operating conditions that affect the efficiency of ultrasound-assisted extraction (UAE) parameters to achieve the best recovery of bioactive compounds from broccoli leaf and floret byproducts. Therefore, total phenolic content (TPC) and the main sulfur bioactive compounds (sulforaphane (SFN) and glucosinolates (GLSs)) were assayed. Distilled water was used as solvent. For each byproduct type, solid/liquid ratio (1:25 and 2:25 g/mL), temperature (25, 40, and 55 °C), and extraction time (2.5, 5, 7.5, 10, 15, and 20 min) were the studied variables to optimize the UAE process by using a kinetic and a cubic regression model. TPC was 12.5-fold higher in broccoli leaves than in florets, while SFN was from 2.5- to 4.5-fold higher in florets regarding the leaf's extracts obtained from the same plants, their precursors (GLS) being in similar amounts for both plant tissues. The most efficient extraction conditions were at 25 °C, ratio 2:25, and during 15 or 20 min according to the target phytochemical to extract. In conclusion, the type of plant tissue and used ratio significantly influenced the extraction of bioactive compounds, the most efficient UAE parameters being those with lower energy consumption.

Anthocyanins: Metabolic Digestion, Bioavailability, Therapeutic Effects, Current Pharmaceutical/Industrial Use, and Innovation Potential

In this work, various concepts and features of anthocyanins have been comprehensively reviewed, taking the benefits of the scientific publications released mainly within the last five years. Within the paper, common topics such as anthocyanin chemistry and occurrence, including the biosynthesis of anthocyanins emphasizing the anthocyanin formation pathway, anthocyanin chemistry, and factors influencing the anthocyanins' stability, are covered in detail. By evaluating the recent in vitro and human experimental studies on the absorption and bioavailability of anthocyanins present in typical food and beverages, this review elucidates the significant variations in biokinetic parameters based on the model, anthocyanin source, and dose, allowing us to make basic assumptions about their bioavailability. Additionally, special attention is paid to other topics, such as the therapeutic effects of anthocyanins. Reviewing the recent in vitro, in vivo, and epidemiological studies on the therapeutic potential of anthocyanins against various diseases permits a demonstration of the promising efficacy of different anthocyanin sources at various levels, including the neuroprotective, cardioprotective, antidiabetic, antiobesity, and anticancer effects. Additionally, the studies on using plant-based anthocyanins as coloring food mediums are extensively investigated in this paper, revealing the successful use of anthocyanins in coloring various products, such as dietary and bakery products, mixes, juices, candies, beverages, ice cream, and jams. Lastly, the successful application of anthocyanins as prebiotic ingredients, the innovation potential of anthocyanins in industry, and sustainable sources of anthocyanins, including a quantitative research literature and database analysis, is performed.

Metabolomic Analysis of Phytochemical Compounds from Agricultural Residues of Eggplant (Solanum melongena L.)

The eggplant is a fruit rich in natural products and produced worldwide. However, its cultivation generates a large amount of scarcely used agricultural residues with poor chemical characterization. This study aimed to identify and quantify the metabolome and determine the composition of select phytochemicals and the overall antioxidant capacity of various anatomical parts of the plant. The plant’s root, leaf, stem, and fruit were analyzed by quantitative mass spectrometry-based untargeted metabolomics and chemoinformatics, and phytochemicals were quantified by spectrophotometric analysis. Moreover, we determined the total antioxidant capacity of the distinct plant parts to infer a possible biological effect of the plant’s metabolites. Various secondary metabolites were identified as terpenes, phenolic compounds, alkaloids, and saponins, distributed throughout the plant. The leaf and fruit presented the highest concentration of phenolic compounds, flavonoids, anthocyanins, and alkaloids, accompanied by the highest antioxidant capacity. Although the stem and root showed the lowest abundance of secondary metabolites, they provided around 20% of such compounds compared with the leaf and fruit. Overall, our study improved the understanding of the eggplant metabolome and concluded that the plant is rich in secondary metabolites, some with antioxidant properties, and shows potential nutraceutical and biopharmaceutical applications.

Advances in Food, Bioproducts and Natural Byproducts for a Sustainable Future: From Conventional to Innovative Processes

The world population is expected to reach almost 10,000 million in 2050, which entails the need to focus on sustainability and its three pillars: the economy, the environment, and society [...]

An Overview on the Use of Response Surface Methodology to Model and Optimize Extraction Processes in the Food Industry

Response surface methodology (RSM) is a widely used tool for modeling and optimization for food processes. The objective of this review is to evaluate recent findings on the use of RSM in the extraction of compounds from agri-food products. First, the steps for the application of RSM were briefly detailed. According to the analysis performed, RSM is suitable because it evaluates the effects of the independent variables and their interactions on the responses, which is ideal for the optimization of different techniques for the extraction of multiple bioactive compounds and therefore, in the various studies, has allowed to significantly increase the yield and even the biological activities of the extracts; however, RSM has limitations and considering the complexity and dynamics of foods, the challenge is much greater. In this sense, it was determined that simultaneous use with other techniques is necessary in order to optimally describe the process and obtain more accurate results.

Purple eggplant and zucchini color, mechanical properties, mastication, and sensory perception influenced by boiling and grilling

The present study investigated the influence of boiling and grilling deployed at 15, 30, and 45 min on selected eggplant and zucchini qualities. The colorants present in these vegetables contribute to their attractive appearance while presenting health-benefit components. This study shows that boiling and grilling differently affected the color properties of the eggplant and zucchini flesh and skin, leading to discoloration. However, the multifactorial mechanisms behind this phenomenon are not yet fully uncovered. Both boiling and grilling caused softening in examined vegetables within cooking prolongation, but different effects were observed. In the case of grilling, large- and small-deformation mechanical parameters established higher values. Thus, grilling produced firmer samples, which was further projected on mastication and dynamic sensory perception. Although there was limited differentiation in mastication parameters, it was observable that grilled products were more mastication-demanding. The number of chews and consumption time provided most of the information and established higher values for short-time cooking treatments and grilling. As a consequence, samples that had longer in-oral exposure times were perceived as bitter (eggplant) or sweet (zucchini). Oppositely, boiled vegetables were juicier. Regardless of the type of vegetable or cooking method, the shortest cooking treatments resulted in products dominantly perceived as firm.

Sustainable Recovery of Preservative and Bioactive Compounds from Food Industry Bioresidues

With the increasing demand for convenient and ready-to-eat foods, the use of antioxidants and preservative additives in foodstuff formulation is essential. In addition to their technological functions in food, bio-based additives confer beneficial properties for human health for having antioxidant capacity and acting as antimicrobial, antitumor, and anti-inflammatory agents, among others. The replacement of preservatives and other additives from synthetic origin, usually related to adverse effects on human health, faces some challenges such as availability and cost. An opportunity to obtain these compounds lies in the food industry itself, as a great variety of food waste has been identified as an excellent source of high value-added compounds. Large amounts of seeds, fibrous strands, peel, bagasse, among other parts of fruits and vegetables are lost or wasted during industrial processing, despite being rich sources of bioactive compounds. From a circular economy perspective, this work reviewed the main advances on the recovery of value-added compounds from food industry bioresidues for food application. Bioactive compounds, mainly phenolic compounds, have been largely obtained, mostly from seeds and peels, and have been successfully incorporated into foods. Additionally, alternative and eco-friendly extraction techniques, as ultrasound and microwave, have showed advantages in extracting antioxidant and preservatives compounds.

Plant-Derived Colorants for Food, Cosmetic and Textile Industries: A Review

This review provides a report on properties and recent research advances in the application of plant-derived colorants in food, cosmetics and textile materials. The following colorants are reviewed: Polyphenols (anthocyanins, flavonol-quercetin and curcumin), isoprenoids (iridoids, carotenoids and quinones), N-heterocyclic compounds (betalains and indigoids), melanins and tetrapyrroles with potential application in industry. Future aspects regarding applications of plant-derived colorants in the coloration of various materials are also discussed.

Green extraction techniques from fruit and vegetable waste to obtain bioactive compounds-A review

Food wastes imply significant greenhouse gas emissions, that increase the challenge of climate change and impact food security. According to FAO (2019), one of the main food wastes come from fruit and vegetables, representing 0.5 billion tons per year, of the 1.3 billion tons of total waste. The wastes obtained from fruit and vegetables have plenty of valuable components, known as bioactive compounds, with many properties that impact positively in human health. Some bioactive compounds hold antioxidant, anti-inflammatory, and anti-cancer properties and they have the capacity of modulating metabolic processes. Currently, the use of fruit and vegetable waste is studied to obtain bioactive compounds, through non-conventional techniques, also known as green extraction techniques. These extraction techniques report higher yields, reduce the use of solvents, employ less extraction time, and improve the efficiency of the process for obtaining bioactive compounds. Once extracted, these compounds can be used in the cosmetic, pharmaceutical, or food industry, the last one being focused on improving food quality.

Valorization of Sicanaodorifera (Vell.) Naudin Epicarp as a Source of Bioactive Compounds: Chemical Characterization and Evaluation of Its Bioactive Properties

Fruit bio-residues can be interesting for the recovery of bioactive molecules, such as phenolic compounds, tocopherols, vitamins, among others. These compounds can be targeted at the food industry and used for the development of functional foods or as food additives. In some cases, fruit epicarps are converted into by-products with non-commercial value, and generally, these fruit parts have a higher content in bioactive compounds than the fruit pulp. From this perspective, S. odorifera, a Brazilian fruit, has an inedible epicarp that could be explored to obtain biological compounds. Therefore, the aims of this study were to evaluate the chemical composition and the antioxidant, anti-proliferative, anti-inflammatory, and antimicrobial bioactivities of this by-product. S. odorifera epicarp showed a total of four organic acids, four phenolic compounds, highlighting the high concentration of anthocyanins (24 ± 1 mg/g dry weight (dw)) and high content of tocopherols (366 ± 2 mg/100 g dw). The hydroethanolic extract showed considerable antioxidant activity (EC₅₀ values of 48.2 ± 0.5 and 27 ± 1 µg/mL for TBARS and OxHLIA assays, respectively), as also antibacterial and antifungal activities (minimal inhibitory concentrations (MICs) ≤ 2.2 mg/mL). The results obtained in this study suggest that Sicana odorifera epicarp represents a reliable option for the development of novel natural-based colorants with functional/bioactive proprieties.