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Emerging Technologies for the Valorization of Agro-Food Byproducts into Functional Ingredients and Foods

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A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Food Process Engineering".

Deadline for manuscript submissions: 15 October 2026 | Viewed by 11355

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Editors

Prof. Dr. Carlos A. Ligarda-Samanez

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Guest Editor

Escuela Profesional de Ingeniería Agroindustrial, Universidad Nacional José María Arguedas, Andahuaylas 03701, Peru
Interests: food engineering; agro-food byproduct valorization; functional foods; bioactive compound microencapsulation; ultrasound processing; sustainable food systems; sensory analysis; innovative food technologies

Prof. Dr. David Choque Quispe

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Guest Editor

Dr. Betsy S. Ramos-Pacheco

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Special Issue Information

Dear Colleagues,

The agro-food industry generates significant amounts of byproducts and residues that are often underutilized or discarded despite their potential as sources of valuable bioactive compounds, fibers, proteins, and antioxidants. In response to the growing demand for sustainable practices and functional foods, developing innovative approaches to transform these byproducts into high-value ingredients has gained significant attention. Emerging technologies such as ultrasound, microwave-assisted extraction, spray-drying, freeze-drying, and microencapsulation, among others, offer efficient and environmentally friendly solutions for this purpose, in line with the principles of the circular economy and the sustainability of food systems.

This Special Issue on "Emerging Technologies for the Valorization of Agro-Food Byproducts into Functional Ingredients and Foods" aims to bring together high-quality original research articles and review papers that explore innovative, sustainable, and efficient processing strategies for converting agro-food byproducts into value-added ingredients and food products. The goal is to highlight recent advances in emerging technologies that enhance the nutritional, functional, physicochemical, and sensory properties of food systems derived from agro-industrial residues. Topics of interest include, but are not limited to, the following:

Microencapsulation of bioactive compounds;
Ultrasound-assisted extraction and processing;
Spray-drying, freeze-drying, and vacuum drying techniques;
Recovery of natural antioxidants, pigments, and dietary fiber;
Fortification and functionalization of food matrices;
Development of novel food products using agro-food byproducts;
Nutritional, techno-functional, and sensory evaluation;
Controlled release systems and bioactive stability;
Use of local biodiversity and underutilized crops;
Circular economy and sustainability in food processing.

Prof. Dr. Carlos A. Ligarda-Samanez
Prof. Dr. David Choque Quispe
Dr. Betsy S. Ramos-Pacheco
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 250 words) can be sent to the Editorial Office for assessment.

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-anonymized peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Processes 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 2400 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

agro-food byproducts
emerging technologies
functional ingredients
bioactive compounds
microencapsulation
ultrasound processing
sustainable food systems
spray-drying
food valorization
circular economy

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Published Papers (9 papers)

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Research

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10 pages, 3077 KB

Open AccessArticle

Tobacco Biowaste Hydrothermal Carbonization: Physicochemical Properties of Hydrochars and Evolution of Active Compounds

by Tengfei Wang, Yinxue Li, Xiao Wei, Zhihui Zhang and Yanling Yu

Processes 2026, 14(13), 2051; https://doi.org/10.3390/pr14132051 - 24 Jun 2026

Viewed by 126

Abstract

The physicochemical characteristics of hydrochars produced from tobacco stems through hydrothermal carbonization (HTC) at different temperatures were investigated, along with the variation in contents of nicotine, niacin, and chlorogenic acid in both the hydrochars and the liquid phase. The results indicated that dehydration was the predominant reaction during HTC of wet tobacco stems (WTS), leading to a decrease in the H/C and O/C atomic ratios of the hydrochars. As temperature increased, polycondensation and aromatization reactions became more pronounced, which corresponded with a reduction in the intensity of functional group vibrations such as C–N and N–O in FT-IR spectra. XPS analysis revealed a gradual increase in C=O content, whereas the proportions of C–OH and C–O bonds declined from 51.74% and 35.13% to 36.95% and 20.84%, respectively. Furthermore, the content of pyridine-N rose from 31.08% to 41.30%, while pyrrole-N and quaternary-N contents decreased to varying degrees. Both nicotine and niacin levels in the hydrochars and carbonization liquids exhibited an initial increase followed by a decline, whereas chlorogenic acid content consistently decreased. The underlying mechanisms for the observed changes in nicotine, niacin, and chlorogenic acid contents during HTC are discussed in detail. Full article

(This article belongs to the Special Issue Emerging Technologies for the Valorization of Agro-Food Byproducts into Functional Ingredients and Foods)

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22 pages, 1142 KB

Open AccessFeature PaperArticle

Stability of Individual Phenolic Compounds and Antioxidant Activity During Storage of a Syrah Grape Seed Extract

by Pamela Georgieva, Yavor Ivanov, Zlatina Chengolova, Gjore Nakov and Tzonka Godjevargova

Processes 2026, 14(11), 1721; https://doi.org/10.3390/pr14111721 - 26 May 2026

Viewed by 883

Abstract

The valorization of winery by-products is a sustainable strategy for receiving valuable bioactive compounds. The aim of this study was to obtain Syrah grape seed extract and investigate the stability of extract phenolic compounds and antioxidant capacity. Separated grape seeds from grape pomace were dried under two different conditions: 23 °C for 10 days and 40 °C for 24 h. Polyphenols were extracted from the dried seeds using 70% aqueous ethanol under magnetic stirring at 600 rpm for 3 h. The yield, color, nutrition value, and mineral contents of the extract were determined. The obtained extracts from the seeds dried at different temperatures were concentrated using a vacuum evaporator. The concentrate was subsequently divided into three forms: liquid, lyophilized, and dried at 40 °C. The individual phenolic components of the lyophilized grape seed extract were determined by HPLC. All extracts were stored at 4 °C and 23 °C for 10 months. The effect of the grape seed drying conditions, extract forms, storage temperature, and time on the total phenolic content, total flavonoids, procyanidins, and antioxidant capacity of the extracts was investigated. Changes in these parameters were evaluated at 0, 3, 6, and 10 months of storage. Degradation kinetics on the basis of antioxidant activity during extracts storage were calculated. Additionally, the individual phenolic composition of liquid and lyophilized Syrah grape seed extracts stored for 10 months was determined by HPLC. The degradation degree of the individual compounds in the extracts was calculated. Full article

(This article belongs to the Special Issue Emerging Technologies for the Valorization of Agro-Food Byproducts into Functional Ingredients and Foods)

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23 pages, 2225 KB

Open AccessArticle

Valorization of Agro-Industrial Waste: Development of Bio-Composite Films from Native Oxalis tuberosa Starch and Keratin Microparticles for Environmental Sustainability

by Diego E. Peralta-Guevara, Fredy Taipe-Pardo, Yasmine Diaz-Barrera, Jhoel Flores-Álvarez and Sofía Pastor-Mina

Processes 2026, 14(11), 1699; https://doi.org/10.3390/pr14111699 - 24 May 2026

Viewed by 228

Abstract

The buildup of non-biodegradable plastic waste and poor management of agro-industrial by-products have caused a major environmental crisis. The present research addresses the development of novel materials supporting the circular bioeconomy. This study aimed to develop and characterize bio-composite films derived from native Oxalis tuberosa starch and keratin microparticles (KMPs) extracted from cattle horn waste. The experimental methodology employed a 2³ factorial design and involved the characterization of the films included the evaluation of physical and optical properties and the identification of functional groups via spectroscopy, mechanical tests, and thermogravimetric analysis (TGA). The results revealed significant interactions (p ≤ 0.05). Higher processing temperatures were the main reason for the drop in water activity (a_w) and moisture content (MC) levels. Concurrently, the incorporation of KMPs reduced water solubility, increased opacity, and enhanced thermal stability. FTIR analysis confirmed the existence of intermolecular interactions between the hydroxyl and amide functional groups. In conclusion, bio-composites composed based on Oxalis tuberosa starch and keratin microparticles represent a sustainable alternative to mitigate the use of conventional plastics in the industry. Full article

(This article belongs to the Special Issue Emerging Technologies for the Valorization of Agro-Food Byproducts into Functional Ingredients and Foods)

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24 pages, 3097 KB

Open AccessArticle

Evaluation of Blue Poppy (Papaver somniferum) By-Products as a Sustainable Source of Polyphenols and Antioxidants

by Danica Božović, Sanja Vojvodić, Uroš Gašić, Viktor Stojkov, Zoran Zeković, Anica Bebek Markovinović, Danijela Bursać Kovačević and Branimir Pavlić

Processes 2026, 14(11), 1683; https://doi.org/10.3390/pr14111683 - 22 May 2026

Viewed by 264

Abstract

The aim of this study was to valorize by-products of blue poppy (Papaver somniferum), a widely used ingredient in the food industry. This study focused on the isolation of bioactive compounds from leaves, stems, roots, capsules and cold-pressed cake. All samples were subjected to conventional solid–liquid extraction (SLE) using ethanol–water solutions of varying concentrations (0, 20, 40, 60, 80 and 96%) as the extraction solvent. The obtained extracts were analyzed for total phenolic content (TP), hydroxycinnamic acids (HCA), flavonols (FL), total flavonoids (TF), condensed tannins (CT) and antioxidant activity. Furthermore, the extracts were subjected to untargeted LC-MS analysis for qualitative characterization. Ethanol concentration significantly influenced the extraction efficiency of bioactive compounds, with the optimal solvent varying depending on the plant part and the specific class of compounds analyzed. Based on TP and TF content, capsule extracts exhibited the highest polyphenol levels. HCAs were detected in extracts from leaves, capsules, and cold-pressed cake. In total, 62 compounds were identified, belonging to various biochemical classes, including organic acids, hydroxycinnamic acids, alkaloids, flavonoids, and fatty acids. Overall, the results indicate that poppy by-products are a valuable source of bioactive components, with promising applications across different industrial sectors. Full article

(This article belongs to the Special Issue Emerging Technologies for the Valorization of Agro-Food Byproducts into Functional Ingredients and Foods)

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21 pages, 3329 KB

Open AccessArticle

Flaxseed Hydrocolloid as a Natural Encapsulating Material for Spray-Dried Phenolic Compounds from Andean Tubers (Oxalis tuberosa and Tropaeolum tuberosum)

by Elibet Moscoso-Moscoso, Dianeth Buleje-Campos, Ronald Perez-Salcedo, David Muñoz-Huachuhuillca and Cristian V. Banda-Arias

Processes 2026, 14(7), 1136; https://doi.org/10.3390/pr14071136 - 1 Apr 2026

Viewed by 590

Abstract

The microencapsulation of plant bioactive compounds by spray drying enhances their stability and controlled delivery in food systems. In this study, flaxseed hydrocolloid (Linum usitatissimum L.) was evaluated as a natural wall material for encapsulating phenolic extracts from mashua (Tropaeolum tuberosum Ruiz & Pav.) and oca (Oxalis tuberosa Molina). Microcapsules were produced using hydrocolloid concentrations of 2.5–10%. The resulting particles showed low moisture content (3.79–5.42%), low water activity (0.31–0.39), and high solubility (90.94–96.45%). Encapsulation efficiency ranged from 78.67 to 62.32% for mashua and from 71.94 to 40.45% for oca, decreasing with increasing wall material concentration. Phenolic content ranged from 14.48 to 11.47 mg GAE/g (mashua) and 8.52 to 4.82 mg GAE/g (oca), with antioxidant capacity between 293.19–143.77 and 84.49–10.33 µmol TE/g, respectively. Particle size ranged from 4.02–10.50 µm (mashua) and 3.93–4.82 µm (oca), and zeta potential values (−37.86 to −27.55 mV) indicated good colloidal stability. Release kinetics showed a biphasic profile and were predominantly diffusion-controlled. The Higuchi model showed significant diffusion (p < 0.05), while the Korsmeyer–Peppas analysis indicated mainly Fickian diffusion (n = 0.234–0.426) with anomalous transport at higher mashua concentrations. These results demonstrate that flaxseed hydrocolloid is an effective and sustainable wall material for controlled release of phenolic compounds from Andean tubers. Full article

(This article belongs to the Special Issue Emerging Technologies for the Valorization of Agro-Food Byproducts into Functional Ingredients and Foods)

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17 pages, 834 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Grape Pomace Flour as a Sustainable Ingredient in Cookie Formulation for Fiber, Free, and Bound Phenols Improvement

by Carlos E. Galindo-Corona, Gloria A. Martinez-Medina, Ricardo Gómez-García, Ayerim Y. Hernández-Almanza, Jorge Armando Meza-Velázquez, Martha Lizeth Quintana-Burciaga, Mariana Mesta-Corral, Cristian Torres-León and Nathiely Ramírez-Guzmán

Processes 2026, 14(3), 410; https://doi.org/10.3390/pr14030410 - 24 Jan 2026

Cited by 1 | Viewed by 1824

Abstract

This study aimed to evaluate the substitution of wheat flour (WF) for grape (Vitis vinifera L.) pomace (GP) on cookie formulation. The techno-functional properties of GP flour (GPF) were characterized, and cookie formulations containing 15% (C15) and 20% (C20) GPF were developed. To evaluate the antioxidant and functional potential, free (FPF, soluble phenols) and bound phenolic fraction (BPF, insoluble phenols) were extracted. The total phenolic content (TPC) and antioxidant potential (ABTS and DPPH assays) were measured. The GPF shows differences in oil and water retention, non-foaming properties, and non-significant differences in swelling capacity compared to WF. C15 and C20 show L* values from 27.9 to 36.2, b* values from 2.22 to 2.64, and a* values from 8.84 to 10.49. GPF addition elevates ash and fiber content by 3.5–4.2 and 14–31.6 times. GPF cookie (C15) exhibited a significantly higher TPC compared to WF. Although the FPF fraction in the cookies was higher compared to BPF, the contribution of BPF to antioxidant activity was high (DPPH = 29.9%, ABTS = 16.3%) compared to FPF (DPPH = 26.3%, ABTS = 20.3%). Given that FPF is traditionally the only antioxidant fraction measured, the antioxidant potential of incorporating grape by-products is being underestimated; this is the first report of this in a cookie. Full article

(This article belongs to the Special Issue Emerging Technologies for the Valorization of Agro-Food Byproducts into Functional Ingredients and Foods)

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18 pages, 3271 KB

Open AccessArticle

The Technological Quality of New Wheat Varieties Grown in the Southern Region of the Central Andes in Perú

by Fredy Taipe-Pardo, Mirian E. Obregón-Yupanqui, Herson Arone-Palomino, Félix Terán-Hilares, Beatriz Núñez-Espinoza and Isaias Ramos-Quispe

Processes 2025, 13(11), 3577; https://doi.org/10.3390/pr13113577 - 6 Nov 2025

Cited by 1 | Viewed by 1202

Abstract

The growing demand of the cereal market, which demands quality products at low cost, has driven the development of new, more accessible wheat varieties. This study evaluated the technological quality of flours obtained from three new wheat varieties produced in Andahuaylas: Espigón de Oro (EOVF), the Gavilón (GVF), and the Andino (AVF) varieties, comparing them with a widely used plain flour (PF). Their proximate parameters, rheological, thermal, and structural properties, elemental composition, and functional groups were analyzed. The local flours (EOVF, GVF, and AVF) presented similar carbohydrate and fat contents, but higher ash, and lower moisture and protein content than plain flour. The rheology and thermal stability showed limitations associated with a less consistent dough and a more fragile structure, indicating lower gluten quality. Differential scanning calorimetry found gelatinization temperatures between 53.42 °C and 57.12 °C, with energy requirements (ΔH) of 1.08 to 1.23 J/g, while thermographic analysis revealed that component degradation began at 150 °C. Scanning electron microscopy micrographs revealed starch granules with varied shapes and a trimodal distribution. Elemental analysis showed a good energy contribution, with 47.9–54.6% carbon and 45.2–51.5% OH. The FT-IR spectra showed similar functional profiles among all the flours. These results suggest that flours from new wheat varieties have a low energy requirement for cooking, making them ideal for extrusion processes and for products with a soft and light texture. They also represent an excellent alternative to commercial flour for developing functional, infant, and easily digestible foods. Full article

(This article belongs to the Special Issue Emerging Technologies for the Valorization of Agro-Food Byproducts into Functional Ingredients and Foods)

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15 pages, 4865 KB

Open AccessFeature PaperArticle

Influence of Ultrasound Frequency as a Preliminary Treatment on the Physicochemical, Structural, and Sensory Properties of Fried Native Potato Chips

by Henry Palomino-Rincón, Betsy S. Ramos-Pacheco, Dianeth Buleje Campos, Rodrigo J. Guzmán Gutiérrez, Evelin M. Yauris-Navez and Elizabeth Alarcón-Quispe

Processes 2025, 13(8), 2668; https://doi.org/10.3390/pr13082668 - 21 Aug 2025

Cited by 2 | Viewed by 2083

Abstract

Frying native potato chips produces snacks that are widely accepted, although they are associated with high fat content and the formation of potentially undesirable compounds. This study evaluated the effect of pretreatment with ultrasound at 28 and 40 kHz on the physicochemical, structural, and sensory properties of chips made from the Sempal and Agustina varieties. The chips were immersed in water and treated with ultrasound for 10 min before frying at 175 °C. Parameters such as moisture, fat content, water activity, color, reducing sugars, FTIR spectroscopy, SEM microscopy, and sensory acceptance by consumers were analyzed. Treatment with 40 kHz significantly reduced fat content (up to 22.07%), improved crispness, and promoted a more porous microstructure. A lower concentration of reducing sugars, greater brightness, and less darkening were also observed. Sensory evaluation showed that chips treated with 40 kHz were the most preferred and best rated in terms of texture and flavor. Finally, it was demonstrated that pretreatment with ultrasound at 40 kHz improved the technological and sensory quality of native potato chips, which would promote the value of these resources in healthy products. Full article

(This article belongs to the Special Issue Emerging Technologies for the Valorization of Agro-Food Byproducts into Functional Ingredients and Foods)

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33 pages, 1359 KB

Open AccessFeature PaperEditor’s ChoiceReview

Development of Functional Fermented Meat Products Using Agro-Food Byproducts

by Yavor Ivanov, Milka Atanasova and Tzonka Godjevargova

Processes 2026, 14(4), 602; https://doi.org/10.3390/pr14040602 - 9 Feb 2026

Viewed by 1383

Abstract

Fermented foods play an important role in human nutrition due to their probiotic properties, improved nutrient absorption and potential health benefits. The incorporation of various agro-food byproducts into them leads to the production of innovative functional foods with even better nutritional properties. In recent years, the application of industrial byproducts has become a hot spot of research, as they are rich in polyphenols, flavonoids, carotenoids, tocopherols, vitamins and anthocyanins, which provide high antioxidant capacity for foods. Among the most popular groups of fermented foods are meat products. The addition of agro-food byproduct powder or extracts to these traditional food products leads to an increase in their nutritional value and antioxidant capacity, a decrease in lipid oxidation and color change, inhibition of the growth of pathogenic microorganisms and the provision of health benefits. The use of these ingredients in the fermentation of meat products is considered to be a promising strategy in the development of new functional fermented meat products. This review will discuss the development of functional fermented meat products by incorporating agro-food byproducts, determining their optimal concentration, studying their impact on the fermentation of the meat products and on its properties and storage, as well as the health benefits of these functional products. Full article

(This article belongs to the Special Issue Emerging Technologies for the Valorization of Agro-Food Byproducts into Functional Ingredients and Foods)

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