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Food Waste and By-Products: Bioactive Compounds, Their Extraction, and Possible Utilization

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A special issue of Foods (ISSN 2304-8158). This special issue belongs to the section "Food Security and Sustainability".

Deadline for manuscript submissions: closed (20 February 2025) | Viewed by 24686

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Prof. Dr. Roger Ruan

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Guest Editor

Center for Biorefining and Department of Bioproducts and Biosystems Engineering, University of Minnesota, 1390 Eckles Ave, St. Paul, MN 55108, USA
Interests: food engineering; value-added processing; food safety assurance; food quality improvement; non-thermal technologies

Dr. Hongli Zheng

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Guest Editor

MOE Biomass Energy Research Center and College of Food Science and Technology, Nanchang University, 235 East Nanjing Road, Nanchang 330047, China
Interests: food biotechnology; enzyme engineering; value-added utilization of food processing byproducts; eco-friendly food
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Special Issue Information

Dear Colleagues,

In recent years, there has been growing interest in the extraction and utilization of food by-products and food waste. The abundance of these materials, coupled with the need for sustainable and environmentally friendly practices, has fueled research in this area. The extraction of valuable compounds from food by-products and food waste has the potential to not only reduce waste and environmental impact, but also to provide valuable resources for various industries.

This Special Issue aims to provide an overview of the current status and future perspectives of these materials in terms of their extraction, analysis, and utilization in the food industry. Potential topics for submission include, but are not limited to:

Extraction methods for valuable compounds from food by-products and food waste.
Characterization and analysis of bioactive constituents in these materials.
Utilization of extracted compounds for the development of functional foods, nutraceuticals, or dietary supplements.
Safety evaluation and toxicological studies on food by-products.
Biotechnological approaches for converting residues into value-added products.
Sustainable management and innovative utilization of food by-products and food waste.

Prof. Dr. Roger Ruan
Dr. Hongli Zheng
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Foods is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

food waste
extraction
utilization
bioactive compounds
characterization
safety assessment
sustainability
functional foods

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Published Papers (10 papers)

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Research

15 pages, 1388 KiB

Open AccessArticle

Mixture Design and Doehlert Matrix for Optimization of Energized Dispersive Guided Extraction (EDGE) of Theobromine and Caffeine from Cocoa Bean Shells

by Luciana Lordêlo Nascimento, Paulo Natan Alves dos Santos, Honnara Santos Granja, Larissa da Silveira Ferreira, João Victor Ferreira Lima, Bruna Louise de Moura Pita, Allan dos Santos Polidoro, Lisiane dos Santos Freitas, Elina Bastos Caramão, Fabio de Souza Dias and Alini Tinoco Fricks

Foods 2025, 14(5), 740; https://doi.org/10.3390/foods14050740 - 21 Feb 2025

Viewed by 863

Abstract

This work describes the development of a method for the extraction of methylxanthines from cocoa bean shell (CBS) by employing the novel Energized Dispersive Guided Extraction (EDGE) system. The mixtures were composed of ethanol–methanol–water and the ratio was optimized using a simplex-centroid design. Doehlert design (DD) was used to optimize the variables of temperature and time while using methylxanthine content obtained by HPLC-DAD as an analytical response. The optimized mixture consisted of water–ethanol in a 3:2 ratio. The optimum operating conditions for extraction were achieved at a temperature of 148.5 °C and 382 s. Under optimal conditions, 20.14 mg g⁻¹ DM of theobromine and 3.53 mg g⁻¹ DM of caffeine were found in the CBS extract. Methylxanthines were quantified with good linearity, LOQs, LODs, precision, and accuracy. The EDGE system, a newly automated extraction instrument, has proven to be very efficient for the recovery of theobromine and caffeine, and is considered a green extraction procedure, as demonstrated by the analytical greenness metric for sample preparation. Full article

(This article belongs to the Special Issue Food Waste and By-Products: Bioactive Compounds, Their Extraction, and Possible Utilization)

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17 pages, 1592 KiB

Open AccessArticle

Antioxidant Maillard Reaction Products from Milk Whey: A Food By-Product Valorisation

by Sara Bolchini, Tiziana Nardin, Ksenia Morozova, Matteo Scampicchio and Roberto Larcher

Foods 2025, 14(3), 450; https://doi.org/10.3390/foods14030450 - 30 Jan 2025

Cited by 2 | Viewed by 1907

Abstract

The Maillard reaction (MR) is a key process in food science, producing bioactive compounds with antioxidant properties. This study evaluates the antioxidant potential of MR products (MRPs) from different dairy byproducts—cow cheese whey, goat cheese whey, and cow yoghurt whey—highlighting their applicability in food preservation and waste valorisation. Whey samples were subjected to the MR at 140 °C for 90 min, showing significant amino acid and sugar consumption, particularly arginine, histidine, and lactose. Using a library of potential antioxidant MRPs (molecular weight < 250 Da), 28 key compounds, including 2-pyrrolecarboxaldehyde and maltol isomer, were identified, primarily in cow cheese whey. A complementary high-molecular-weight MRP library (≥250 Da) identified 72 additional antioxidant compounds, with distinct production patterns linked to whey type. Multivariate analyses confirmed that whey type strongly influences MRP profiles. These results highlight the potential of MR to transform whey by-products into valuable sources of natural antioxidants. This approach offers sustainable strategies for enhancing food preservation, reducing food waste, and supporting the targeted use of MRPs in the food industry. Full article

(This article belongs to the Special Issue Food Waste and By-Products: Bioactive Compounds, Their Extraction, and Possible Utilization)

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17 pages, 4597 KiB

Open AccessArticle

Preparation, Structural Characterization, and Hypoglycemic Activity of Dietary Fiber from Sea Buckthorn Pomace

by Qi Xiao, Liting Yang, Jingjing Guo, Xiyu Zhang, Yu Huang and Qun Fu

Foods 2024, 13(22), 3665; https://doi.org/10.3390/foods13223665 - 18 Nov 2024

Cited by 3 | Viewed by 1404

Abstract

Sea buckthorn pomace is often discarded as a by-product during the sea buckthorn processing stage. Consequently, its richness in dietary fiber is usually overlooked. In this study, soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) were extracted from sea buckthorn pomace using ultrasound combined with the enzyme method. The optimal values of the independent variable were determined by a combinatorial design and a response surface optimization test with SDF/IDF as the dependent variable, prepared as follows: 5% enzyme addition, ultrasonic power of 380 W, enzymatic time of 30 min, and alcoholic precipitation liquid ratio of 4:1. Under these conditions, the SDF/IDF ratio was 17.07%. The structural characterization and hypoglycemic activity of the two dietary fibers were then compared. The results show that two dietary fibers have respective structures and functional groups of fibers. SDF was less crystalline than IDF, and its structure was looser. Furthermore, the hypoglycemic activity of SDF was significantly better than IDF’s (p < 0.05). The glucose adsorption capacity of SDF was 1.08–1.12 times higher than that of IDF. SDF inhibited α-amylase and α-glucosidase by 1.76 and 4.71 times more than IDF, respectively. These findings provide a reference for improving the utilization of sea buckthorn processing by-products. Full article

(This article belongs to the Special Issue Food Waste and By-Products: Bioactive Compounds, Their Extraction, and Possible Utilization)

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11 pages, 1292 KiB

Open AccessArticle

Brown Seaweed Byproduct Extracts Improve Intestinal Motility and Auto-Inflammation in Mice with Loperamide-Induced Constipation

by Eun-Jeong Koh, Kwang-Soon Shin, In Yung Sunwoo, Junseong Kim and Woon-Yong Choi

Foods 2024, 13(13), 2037; https://doi.org/10.3390/foods13132037 - 27 Jun 2024

Cited by 5 | Viewed by 2065

Abstract

Sargassum fusiforme and Sargassum fulvellum are types of brown algae used for their nutritional value and medicinal properties, including anti-inflammatory, antioxidant, and anticancer effects. Despite their importance in various industries, many seaweed byproducts containing dietary fiber and polysaccharides are discarded in landfills. These byproducts can be recycled and repurposed for different applications. In this study, we investigated the impact of S. fusiforme food processing byproducts (MbP-SFF) and S. fulvellum food processing byproducts (MbP-SFV) on improving intestinal motility and reducing inflammation in mice with constipation induced by loperamide. To evaluate this, mice were orally administered 500 mg/kg/day of the byproducts once daily for 8 days. Constipation was induced by 5 mg/kg/day of loperamide for two days after oral administration for 6 days. Each sample contained approximately 70% carbohydrates. MbP-SFF had 52.0% mannuronic acid and 18.8% guluronic acid, while MbP-SFV had 36.9% mannuronic acid and 32.9% guluronic acid. These byproducts enhanced fecal excretion and intestinal motility by modulating inflammatory responses. Furthermore, they restored the balance of the gut microbiota disrupted by loperamide, increasing beneficial Bifidobacterium and reducing harmful Staphylococcus aureus. Overall, MbP-SFF and MbP-SFV improved intestinal motility and inflammation by influencing the gut microbiota and inflammatory responses in a loperamide-induced mouse model. These byproducts show potential as ingredients in functional foods aimed at enhancing gut health, potentially reducing waste disposal costs and addressing environmental concerns associated with their utilization. Full article

(This article belongs to the Special Issue Food Waste and By-Products: Bioactive Compounds, Their Extraction, and Possible Utilization)

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18 pages, 481 KiB

Open AccessEditor’s ChoiceArticle

The Nutritional Potential of Avocado By-Products: A Focus on Fatty Acid Content and Drying Processes

by Roko Marović, Marija Badanjak Sabolović, Mladen Brnčić, Antonela Ninčević Grassino, Kristina Kljak, Sandra Voća, Sven Karlović and Suzana Rimac Brnčić

Foods 2024, 13(13), 2003; https://doi.org/10.3390/foods13132003 - 25 Jun 2024

Cited by 13 | Viewed by 4314

Abstract

The aim of this study was to analyze the content of fatty acids and tocopherols in various components (pulp, seeds, peel) of avocado (Persea americana), which are often neglected as by-products. In addition, the effects of different drying processes on these components were investigated and the health benefits of the main fatty acids contained in avocados were highlighted. The samples were subjected to three drying processes: hot air (HAD), vacuum (VD), and hot-air microwave (HAMD). In all parts of fresh avocado, oleic acid was the most abundant (41.28–57.93%), followed by palmitic acid (19.90–29.45%) and linoleic acid (8.44–14.95%). Drying led to a significant reduction in the oleic acid content, with palmitic acid showing the greatest stability. HAD resulted in higher levels of oleic acid and linoleic acid in dried pulp and peel samples compared with VD and HAMD, while HAMD had the highest content of α-linolenic acid in all parts. In addition, HAMD had the shortest drying time. HAMD duration was 35 min, which was 76.7% shorter than HAD (150 min) and 82.5% shorter than VD (200 min). Considering fatty acid retention and drying efficiency, HAMD appears to have been the most effective method, especially for the avocado peel. Remarkably, the avocado peel consistently contained higher total tocopherol, with δ-tocopherol generally being the most abundant form. The high content of tocopherols, oleic acid, and linoleic acid in the avocado peel suggests promising health benefits. Full article

(This article belongs to the Special Issue Food Waste and By-Products: Bioactive Compounds, Their Extraction, and Possible Utilization)

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14 pages, 1015 KiB

Open AccessArticle

Single-Cell Protein and Ethanol Production of a Newly Isolated Kluyveromyces marxianus Strain through Cheese Whey Valorization

by Danai Ioanna Koukoumaki, Seraphim Papanikolaou, Zacharias Ioannou, Ioannis Mourtzinos and Dimitris Sarris

Foods 2024, 13(12), 1892; https://doi.org/10.3390/foods13121892 - 16 Jun 2024

Cited by 7 | Viewed by 2787

Abstract

The present work examined the production of single-cell protein (SCP) by a newly isolated strain of Kluyveromyces marxianus EXF-5288 under increased lactose concentration of deproteinized cheese whey (DCW) and different temperatures (in °C: 20.0, 25.0, 30.0 and 35.0). To the best of the authors’ knowledge, this is the first report examining the ability of Kluyveromyces marxianus species to produce SCP at T = 20.0 °C. Different culture temperatures led to significant differences in the strain’s growth, while maximum biomass and SCP production (14.24 ± 0.70 and 6.14 ± 0.66 g/L, respectively) were observed in the cultivation of K. marxianus strain EXF-5288 in shake-flask cultures at T = 20.0 °C. Increased DCW lactose concentrations (35.0–100.0 g/L) led to increased ethanol production (Eth_max = 35.5 ± 0.2 g/L), suggesting that K. marxianus strain EXF-5288 is “Crabtree-positive”. Batch-bioreactor trials shifted the strain’s metabolism to alcoholic fermentation, favoring ethanol production. Surprisingly, K. marxianus strain EXF-5288 was able to catabolize the produced ethanol under limited carbon presence in the medium. The dominant amino acids in SCP were glutamate (15.5 mg/g), aspartic acid (12.0 mg/g) and valine (9.5 mg/g), representing a balanced nutritional profile Full article

(This article belongs to the Special Issue Food Waste and By-Products: Bioactive Compounds, Their Extraction, and Possible Utilization)

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20 pages, 1589 KiB

Open AccessArticle

Exploring the Untapped Potential of Pine Nut Skin By-Products: A Holistic Characterization and Recycling Approach

by Agata Nolasco, Jonathan Squillante, Salvatore Velotto, Giovanni D’Auria, Pasquale Ferranti, Gianfranco Mamone, Maria Emanuela Errico, Roberto Avolio, Rachele Castaldo, Lucia De Luca, Raffaele Romano, Francesco Esposito and Teresa Cirillo

Foods 2024, 13(7), 1044; https://doi.org/10.3390/foods13071044 - 28 Mar 2024

Cited by 3 | Viewed by 2605

Abstract

The increasing population, food demand, waste management concerns, and the search for sustainable alternatives to plastic polymers have led researchers to explore the potential of waste materials. This study focused on a waste of pine nut processing referred to in this paper as pine nut skin. For the first time, its nutritional profile, potential bioactive peptide, contaminants, and morphological structure were assessed. Pine nut skin was composed mainly of carbohydrates (56.2%) and fiber (27.5%). The fat (9.8%) was about 45%, 35%, and 20% saturated, monounsaturated, and polyunsaturated fatty acid, respectively, and Omega-9,-6, and -3 were detected. Notably, oleic acid, known for its health benefits, was found in significant quantities, resembling its presence in pine nut oil. The presence of bioactive compounds such as eicosapentaenoic acid (EPA) and phytosterols further adds to its nutritional value. Some essential elements were reported, whereas most of the contaminants such as heavy metals, polycyclic aromatic hydrocarbons, rare earth elements, and pesticides were below the limit of quantification. Furthermore, the in silico analysis showed the occurrence of potential precursor peptides of bioactive compounds, indicating health-promoting attributes. Lastly, the morphological structural characterization of the pine nut skin was followed by Fourier Transform Infrared and solid-state NMR spectroscopy to identify the major components, such as lignin, cellulose, and hemicellulose. The thermostability of the pine nut skin was monitored via thermogravimetric analysis, and the surface of the integument was analyzed via scanning electron microscopy and volumetric nitrogen adsorption. This information provides a more comprehensive view of the potential uses of pine nut skin as a filler material for biocomposite materials. A full characterization of the by-products of the food chain is essential for their more appropriate reuse. Full article

(This article belongs to the Special Issue Food Waste and By-Products: Bioactive Compounds, Their Extraction, and Possible Utilization)

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17 pages, 1286 KiB

Open AccessEditor’s ChoiceArticle

HPLC-MS/MS Phenolic Characterization of Olive Pomace Extracts Obtained Using an Innovative Mechanical Approach

by Ilaria Grigoletto, Patricia García Salas, Enrico Valli, Alessandra Bendini, Federico Ferioli, Federica Pasini, Sebastián Sánchez Villasclaras, Roberto García-Ruiz and Tullia Gallina Toschi

Foods 2024, 13(2), 285; https://doi.org/10.3390/foods13020285 - 16 Jan 2024

Cited by 7 | Viewed by 3348

Abstract

Olive pomace results from the production of olive oil. Even if olive pomace represents a potential environmental problem, it contains phenolic compounds, which are widely recognized for their beneficial properties for human health. In this study, an innovative and sustainable technological approach to extract phenolic compounds from fresh olive pomace, based on food-grade solvent instead of those usually adopted, is investigated. Characterization and shelf-life evaluation of the hydroalcoholic extracts obtained from the procedure developed for different industrial purposes were also carried out. The phenolic fractions of the different samples were studied with the Folin–Ciocâlteu method to quantify that the total reducing molecules and HPLC-MS/MS analysis was used to define the profile through the identification and quantification of 42 compounds, belonging to five chemical families. Regarding shelf-life, the hydroalcoholic extract showed no significant reduction in phenolic content, for both instrumental evaluations, retaining most of the phenolic compounds present in the raw material; negative attributes were not perceived by sensory evaluation. Thus, these lab-scale results can be the starting point to develop a procedure that is suitable for a real olive mill, representing a valorization strategy in a circular economy and the perspective of new business models. Full article

(This article belongs to the Special Issue Food Waste and By-Products: Bioactive Compounds, Their Extraction, and Possible Utilization)

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15 pages, 303 KiB

Open AccessArticle

Exploring the Bioactive Content of Liquid Waste and Byproducts Produced by Two-Phase Olive Mills in Laconia (Greece): Is There a Prospect for Added-Value Applications?

by Ioanna Pyrka, Christina Koutra, Vasileios Siderakis, Panagiotis Stathopoulos, Alexios-Leandros Skaltsounis and Nikolaos Nenadis

Foods 2023, 12(24), 4421; https://doi.org/10.3390/foods12244421 - 9 Dec 2023

Cited by 3 | Viewed by 1796

Abstract

The use of a two-phase decanter (TwPD) for olive-oil extraction produces wastes and byproducts (a small volume of water from oil washing, olive leaves from the defoliator, and a high moisture pomace which can be destoned) that contain valuable bioactive compounds, such as phenolics and/or triterpenic acids. So far, there is no (water) or limited information (leaves and the destoned pomace fraction) on their content of bioactives, especially triterpenic acids. To contribute to the characterization of such streams from cultivars of international interest, in the present study, samples obtained from five mills from the region of Laconia (from one or two harvests) in Greece, where Koroneiki cv dominates, were screened for phenols and/or triterpenic acids. The leaves and pomace were dried at two temperatures (70 °C and/or 140 °C), and the pomace was also destoned before analysis. The liquid wastes contained low amounts of total (TPC) phenols (<140 mg gallic acid/L), hydroxytyrosol (<44 mg/L), and tyrosol (<33 mg/L). The olive leaves varied widely in TPC (12.8–57.4 mg gallic acid/g dry leaf) and oleuropein (0.4–56.8 mg/g dry leaf) but contained an appreciable amount of triterpenic acids, mainly oleanolic acid (~12.5–31 mg/g dry leaf, respectively). A higher drying temperature (140 vs. 70 °C) affected rather positively the TPC/oleuropein content, whereas triterpenic acids were unaffected. The destoned pomace TPC was 15.5–22.0 mg gallic acid/g dw, hydroxytyrosol 3.9–5.6 mg/g dw, and maslinic 5.5–19.3 mg/g dw. Drying at 140 °C preserved better its bioactive phenols, whereas triterpenic acids were not influenced. The present findings indicate that TwPD streams may have a prospect as a source of bioactives for added-value applications. Material handling, including drying conditions, may be critical but only for phenols. Full article

(This article belongs to the Special Issue Food Waste and By-Products: Bioactive Compounds, Their Extraction, and Possible Utilization)

17 pages, 9278 KiB

Open AccessArticle

Acute Oral Toxicity Evaluation of Almond Hull Powders in BALB/c Mice

by Juer Liu, Yuyang Yao, Yanling Cheng, Wei Hua, Xinyue Zhu, Qiming Miao, Guangwei Huang, Shengquan Mi and Roger Ruan

Foods 2023, 12(22), 4111; https://doi.org/10.3390/foods12224111 - 13 Nov 2023

Cited by 5 | Viewed by 2144

Abstract

Almond hull, a substantial byproduct constituting more than half of almond fresh weight, has garnered recent attention due to its abundance in fiber and bioactive content. Despite this huge interest, data on its toxicity remain scarce. In line with the Organization for Economic Cooperation and Development (OECD) 423 guidelines, this study conducted an acute oral toxicity test using almond hull powders processed from three major almond varieties of Butte, Monterey, and Nonpareil on BALB/c female mice, administering dosages of 300 mg/kg body weight (bw), 2000 mg/kg bw, and 5000 mg/kg bw, with observations over a 14-day period. The results indicated that almond hull powders were non-toxic, aligning with the Globally Harmonized System’s classification. Administering up to 5000 mg/kg bw of all three varieties of almond hull powders (female BALB/c mice) and 10,000 mg/kg bw of Monterey almond hull powders (both female and male mice) induced no adverse effects in terms of mortality, body weight changes, food intake, organ to weight ratio, and clinical biochemistry. Additionally, histopathological examination revealed no organ abnormalities. This study demonstrates the non-toxic nature of almond hull as an edible food ingredient under experimental conditions, encouraging the further exploration of its potential for safe consumption and its health benefits. Full article

(This article belongs to the Special Issue Food Waste and By-Products: Bioactive Compounds, Their Extraction, and Possible Utilization)

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