Agri-food industries generate enormous amounts of fruit and vegetable processing wastes, which opens up an important research area aimed towards minimizing and managing them efficiently to support zero wastes and/or circular economy concept. These wastes remain underutilized owing to a lack of appropriate processing technologies vital for their efficient valorization, especially for recovery of health beneficial bioactives like dietary fibers. Dietary fiber finds wide applications in food and pharmaceutical industries and holds high promise as a potential food additive and/or as a functional food ingredient to meet the techno-functional purposes important for developing health-promoting value-added products. Based on this, the present review has been designed to support ‘zero waste’ and ‘waste to wealth’ concepts. In addition, the focus revolves around providing updated information on various sustainability challenges incurred towards valorization of fruit and vegetable wastes for extraction of health promoting dietary fibers.

Sea buckthorn pomace is a valuable industrial waste/by-product obtained after juice production that contains bioactive, health-promoting dietary fibres. This pomace finds usage as animal feed or simply discarded, owed to the lack of appropriate handling or processing facilities. The present study was aimed to evaluate the effects of green extraction technologies such as ultrasonic-assisted extraction on the yield of soluble dietary fibre (SDF) from sea buckthorn pomace. Response surface methodology (RSM) coupled with Box–Behnken design (BBD) was applied for optimization of SDF yield. The effects of sonication temperature (60–80 °C), sonication power (100–130 W) and extraction time (30–60 min) on the yield of SDF were also investigated. Furthermore, colour measurement and hydration properties of sea buckthorn pomace powder (STP) and dietary fibre fractions (SDF and insoluble dietary fibre, IDF) were also investigated. From the RSM results, the optimal sonication temperature (67.83 °C), sonication power (105.52 W) and extraction time (51.18 min) were identified. Based on this, the modified optimum conditions were standardised (sonication temperature of 70 °C, sonication power of 105 W and extraction time of 50 min). Accordingly, the yield of SDF obtained was 16.08 ± 0.18%, which was close to the predicted value (15.66%). Sonication temperature showed significant effects at p ≤ 0.01, while sonication power and extraction time showed significant effects at p ≤ 0.05 on the yield of SDF. The result on colour attributes of STP, SDF and IDF differed (L* (STP: 54.71 ± 0.72, IDF: 72.64 ± 0.21 and SDF: 54.53 ± 0.31), a* (STP: 52.35 ± 1.04, IDF: 32.85 ± 0.79 and SDF: 43.54 ± 0.03), b* (STP: 79.28 ± 0.62, IDF: 82.47 ± 0.19 and SDF: 71.33 ± 0.50), and ∆E* (STP: 79.93 ± 0.50, IDF: 74.18 ± 0.30 and SDF: 68.40 ± 0.39)). Higher values of hydration properties such as the water holding, swelling and oil holding capacities were found in SDF (7.25 ± 0.10 g g⁻¹, 7.24 ± 0.05 mL g⁻¹ and 1.49 ± 0.02 g g⁻¹), followed by IDF (6.30 ± 0.02, 5.75 ± 0.07 and 1.25 ± 0.03) and STP (4.17 ± 0.04, 3.48 ± 0.06 and 0.89 ± 0.03), respectively. Based on our results, response surface methodology is recommended to be adopted to optimize the ultrasonic-assisted extraction to obtain maximum yield of SDF from sea buckthorn pomace. These results can be of practical usage while designing future functional food formulations using sea buckthorn pomace.

Blackcurrants are sources of phenolic compounds, such as anthocyanins, possessing strong antioxidant, antimicrobial and antifungal activity. Therefore, the addition of different blackcurrant pomace ingredients may affect the overall meat quality. The actual chemical profile and bioactivities of blackcurrant pomace ingredients may strongly depend on its preparation; for instance, in our study the highest values of the in vitro antioxidant capacity were determined for blackcurrant seeds after supercritical CO₂ extraction. Starting from these background conditions, in this work, we evaluated the ability of three different concentrations (namely 1, 3, and 5% w/w) of blackcurrant (BC) seeds following EtOH/water extraction (BC-AE), before supercritical fluid CO₂ extraction (BC-RS), and after supercritical fluid CO₂ extraction (BC-ASC) to affect different quality parameters of pork meatballs. These latter were stored considering three different time-points, namely 1, 3 and 6 days at 4 °C packed under modified atmosphere (i.e., 70% N₂ and 30% CO₂). Untargeted metabolomics allowed to identify several lipid and protein-related oxidation products involved in redox reactions, such as 13-L-hydroperoxylinoleic acid, (12S,13S)-epoxylinolenic acid, 9,10-epoxyoctadecenoic acid, glutathione, glutathione disulfide, L-carnosine, l-ascorbic acid, and tocotrienols. Besides, multivariate statistics applied on the metabolomics dataset confirmed that the chemical profile of meatballs was an exclusive combination of both BC inclusion levels and type of BC-ingredients considered. Our findings showed that the higher the concentration of BC seed ingredients in meatballs, the lower the cooking loss and the higher the fibre content. Also, all the ingredients significantly affected the colour parameters.

The berry pomace could be a potential source for food applications due to its high content of polyphenols, but also dietary fiber, PUFAs and pectin. This is the first study that aims to compare the total dietary fiber (TDF), protein, fat, mineral, pectin and fatty acid content of the following 16 different pomace samples of Sorbus aucuparia L. cultivars (cvs): ‘Likernaja’, ‘Burka’, ‘Alaja Krupnaja’, ‘Granatnaja’, ‘Rubinovaja’, ‘Bussinka’, ‘Vefed’, ‘Angri’, ‘Krasnaja’, ‘Solnechnaja’, ‘Sahharnaja’, ‘Oranzevaja’, ‘Kubovaja’, ‘Moravica’, ‘Rosina’ and ‘Rossica’, in order to find new natural materials for valorization. The contents of pectin and dietary fibers were analyzed using the respective Megazyme enzymatic kits. The TDF content was the highest in the pomace samples of hybrid cvs ‘Granatnaja’ (63.04% dry mass DM), ‘Burka’ (64.52% DM), ‘Rubinovaja’ (65.66% DM) and ‘Likernaja’ (67.17% DM). The pomace of hybrid cv ‘Rubinovaja’ was distinguished from other samples by its high protein content, cv ‘Alaja Krupnaja’ by its high pectin content and cv ‘Oranzevaja’ by its high fat content, which were 7.58% DM, 8.39% DM and 7.47% DM, respectively. The pomace of cv ‘Sahharnaja’ possessed the highest average macro-element content (1.56 g/kg DM). The average fatty acids profile was characterized by a high content of linoleic acid (51.94%), oleic acid (20.55%) and palmitic acid (12.96%). The lowest n6/n3 ratio was found in the hybrid cv ‘Alaja Krupnaja’ (6.70%). The data obtained demonstrate that the pomaces of certain cultivars of rowanberry contain significant amounts of valuable components, which can be used in functional food and cosmetic applications.