Biotechnological Methods of Management and Utilization of Potato Industry Waste—a Review

Umami Enhancing Properties of Enzymatically Hydrolyzed Mycelium of Flammulina velutipes Cultured on Potato Pulp

The aim of this study was to hydrolyze cultivated fungal mycelium and to evaluate the effect on its taste. Potato pulp, a by-product of the potato starch industry, was therefore successfully utilized as a substrate for submerged cultivation of Flammulina velutipes, yielding a product with an estimated fungal content of 83% ± 3%. The fermentation increased the protein content from 5.3 ± 0.4 g/100 g DM to 13.9 ± 0.1 g/100 g DM with a biological protein value of 86. The fermentate was enzymatically hydrolyzed by Corolase APC-peptidase. After optimization of the hydrolysis conditions, a degree of hydrolysis (DH) of 75.1% ± 1.0% was achieved. The protein hydrolysis increased the contents of free glutamate more than 20-fold from 8.7 ± 0.1 mg/L to 188.7 ± 1.2 mg/L. Elevated glutamate levels led to an umami taste perception in aqueous solution and taste-enhancing properties in vegetable broth. Noteworthy, the fermentate itself exhibited an intrinsic peptidase activity. Without addition of auxiliary peptidases, mycelial enzymes caused a DH of 33.9% ± 0.7% and a free glutamate content of 99.1 ± 0.7 mg/L. For these samples, an increase in umami taste was only observed in vegetable broth, but not in water, indicating taste-enhancing properties but low umami taste. In addition to the nutritional and health benefits of fungi, their hydrolysates are of great interest for use as a protein booster with flavor-enhancing properties.

Optimization of fermentation conditions for microbial transglutaminase production by Streptoverticillium cinnamoneum KKP 1658 using response surface methodology (RSM)

Microbial transglutaminase (MTG) is an enzyme widely used in the food industry because it creates cross-links between proteins, enhancing the texture and stability of food products. Its unique properties make it a valuable tool for modifying the functional characteristics of proteins, significantly impacting the quality and innovation of food products. In this study, response surface methodology was employed to optimize the fermentation conditions for microbial transglutaminase production by the strain Streptoverticillium cinnamoneum KKP 1658. The effects of nitrogen dose, cultivation time, and initial pH on the activity of the produced transglutaminase were investigated. The significance of the examined factors was determined as follows: cultivation time > nitrogen dose > pH. The interaction between nitrogen dose and cultivation time was found to be crucial, having the second most significant impact on transglutaminase activity. Optimal conditions were identified as 48 h of cultivation with a 2% nitrogen source dose and an initial medium pH of approximately 6.0. Under these conditions, transglutaminase activity ranged from 4.5 to 5.5 U/mL. The results of this study demonstrated that response surface methodology is a promising approach for optimizing microbial transglutaminase production. Future applications of transglutaminase include the development of modern food products with improved texture and nutritional value, as well as its potential use in regenerative medicine for creating biomaterials and tissue scaffolds. This topic is particularly important and timely as it addresses the growing demand for innovative and sustainable solutions in the food and biomedical industries, contributing to an improved quality of life.

The polysaccharide from purple sweet potato (Ipomoea batatas (L.) Lam) alleviates lipopolysaccharide-induced acute lung injury in mice via the VIP/cAMP/PKA/AQPs signaling pathway

BACKGROUND

The polysaccharide (PSP) from purple sweet potato has great potential for regulating apoptosis, but its regulatory role in acute lung injury (ALI) is unknown.

METHODS

The objective of this study was to investigate the protective effect of PSP on lipopolysaccharide (LPS)-induced ALI in mice and lung epithelial A549 cells and its mechanism. Moreover, subacute toxicity evaluation of PSP was carried out on ICR mice.

RESULTS

The results showed that compared with the ALI group, PSP significantly reduced the total protein content, wet-to-dry (W/D) ratio, the number of neutrophils, lymphocytes, and monocytes. Moreover, PSP was able to reduce cell apoptosis, the levels of macrophage inflammatory protein-2 (MIP-2), intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor-α (TNF-α), malondialdehyde (MDA) and myeloperoxidase (MPO) and increase the level of superoxide (SOD). In addition, PSP could up-regulate the levels of VIP, cAMP, p-PKA/PKA and AQP1 in mice and A549 cells. And PSP exhibited no apparent adverse effects on the mice.

CONCLUSIONS

PSP had a protective effect on LPS-induced ALI in mice and lung epithelial A549 cells, which may be related to the inflammatory response and via VIP/cAMP/PKA/AQPs signaling pathway. Thus, PSP may be a promising pharmacologic agent for ALI therapy.

YourTuber matters: Screening for potato variety for the synthesis of bacterial cellulose in its tuber juice

This study aimed to characterize potato varieties for producing potato juice media (PJM) that allow bacterial cellulose (BC) effective and cost-efficient production. The study used 12 edible and 10 starch potato varieties from an accredited company for breeding and seed production. In general, edible varieties produced a 73 % higher PJ yield. Favorable BC yields were obtained using five edible and two starch varieties. Notably, the average BC yields in PJM from three edible varieties (Altesse, Mazur, and Owacja) were above the average BC yield from Hestrin-Schramm (HS) medium (4.3, 4.1, and 3.9 g/L v. 3.69 g/L, respectively); these varieties had relatively high concentrations of glucose (3.3-4.2 g/L), fructose (3.0-4.2 g/L), and sucrose (2.9-4.2 g/L). It was also shown that the macro- and microstructure, crystallinity, and polymerization degree showed no significant differences between PJM-derived BC and HS-BC. As estimated, the cost of PJM required to produce 1 kg of BC is approximately EUR 60. In contrast, the cost of HS medium exceeds 1200 EUR. In conclusion, our research has proven that PJM can significantly reduce the costs (by over tenfold) of the medium for BC biosynthesis, ultimately lowering overall costs of producing this valuable biomaterial.

Biotechnological Innovations Unleashing the Potential of Olive Mill Wastewater in Added-Value Bioproducts

Byproducts and wastes from the food processing industry represent an important group of wastes generated annually in large quantities. It is important to note that the amount of this waste will increase with industrialization, and effective solutions must be found urgently. Many wastes that cause environmental pollution are evaluated by their low-tech conversion into products with little economic value, such as animal feed and fertilizer. Therefore, the evaluation of food processing waste using effective recycling techniques has become an interesting subject with increasing population, ongoing biotechnological studies, and advances in technology. The conversion of food waste into biotechnological products via fermentation is a sustainable, environmentally friendly, and economical method in line with the principles of green chemistry. This approach promotes the reuse of food waste by supporting the principles of a circular economy and offers sustainable alternatives to fossil fuels and synthetic chemicals. This contributes to reducing the carbon footprint, preserving soil and water quality, and providing economic sustainability through the production of high-value products. In this study, the properties of olive mill wastewater, an important and valuable waste in the olive oil industry, its environmental aspects, and its use in biotechnological applications that integrate green chemistry are evaluated.

Potato Berries as a Valuable Source of Compounds Potentially Applicable in Crop Protection and Pharmaceutical Sectors: A Review

Potato (Solanum tuberosum) is a major agricultural crop cultivated worldwide. To meet market demand, breeding programs focus on enhancing important agricultural traits such as disease resistance and improvement of tuber palatability. However, while potato tubers get a lot of attention from research, potato berries are mostly overlooked due to their level of toxicity and lack of usefulness for the food production sector. Generally, they remain unused in the production fields after harvesting the tuber. These berries are toxic due to high levels of glycoalkaloids, which might confer some interesting bioactivities. Berries of various solanaceous species contain bioactive secondary metabolites, suggesting that potato berries might contain similarly valuable metabolites. Therefore, possible applications of potato berries, e.g., in the protection of plants against pests and pathogens, as well as the medical exploitation of their anti-inflammatory, anticarcinogenic, and antifungal properties, are plausible. The presence of valuable compounds in potato berries could also contribute to the bioeconomy by providing a novel use for otherwise discarded agricultural side streams. Here we review the potential use of these berries for the extraction of compounds that can be exploited to produce pharmaceuticals and plant protection products.

Polyphasic identification of Rhizopus oryzae and evaluation of physical fermentation parameters in potato starch processing liquid waste for β-glucan production

Β-glucans are polysaccharide macromolecules that can be found in the cell walls of molds, such as Rhizopus oryzae. They provide functional properties in food systems and have immunomodulatory activity, anticancer, and prebiotic effects; reduce triglycerides and cholesterol; and prevent obesity, among others benefits. Furthermore, potato starch production requires a large amount of water, which is usually discharged into the environment, creating problems in soils and bodies of water. The physical parameters to produce β-glucans were determined, liquid waste from potato starch processing was used and native Rhizopus oryzae was isolated and identified from cereal grains. The isolates grew quickly on the three types of agars used at 25 °C and 37 °C, and they did not grow at 45 °C. Rhizopus oryzae M10A1 produced the greatest amount of β-glucans after six days of culture at 30 °C, pH 6, a stirring rate of 150 rpm and a fermentation volume of 250 mL. By establishing the physical fermentation parameters and utilizing the liquid waste from potato starch, Rhizopus oryzae M10A1 yielded 397.50 mg/100 g of β-glucan was obtained.

Possible Options for Utilization of EU Biomass Waste: Pyrolysis Char, Calorific Value and Ash Content

The application of biomass as a co-feed in coal power plants and in standalone biomass power plants, as well as in char production for soil remediation, is a currently important issue. This paper reports on the investigation of biochar formation from agricultural waste crops that are used for soil upgrading, but which do not meet the standards of EU crops, as well as largescale food processing waste. These were compared to test results from basket willow, which is commonly used for energy generation. Food industry waste is often produced in cities on a large scale and is generally easier to process due to lack of other stream components. The key parameters, namely, the content of volatiles, energy content of the formed biochar and the composition of the ash, were determined for a number of herbaceous materials locally available in the European Union. All of them can be used as a cheap source of biochar. A novel procedure of capturing volatiles and hence minimizing the PAH content in the biochar, as well as enabling the recovery of energy from the volatiles is presented. Knowledge of the composition and form of elements in ash is very important for designing ash management systems if co-combustion is implemented. The aim of this study was to determine if the types of biomass are better suited for biochar production or energy generation.

Valorization of fruit and vegetable processing by-products/wastes

Fruit and vegetable processing by-products and wastes are of great importance due to their high production volumes and their composition containing different functional compounds. Particularly, apple, grape, citrus, and tomato pomaces, potato peel, olive mill wastewater, olive pomace and olive leaves are the main by-products that are produced during processing. Besides conventional techniques, ultrasound-assisted extraction, microwave-assisted extraction, pressurized liquid extraction (sub-critical water extraction), supercritical fluid extraction, enzyme-assisted extraction, and fermentation are emerging tools for the recovery of target compounds. On the other hand, in the view of valorization, it is possible to use them in active packaging applications, as a source of bioactive compound (oil, phenolics, carotenoids), as functional ingredients and as biofertilizer and biogas sources. This chapter explains the production of fruit and vegetable processing by-products/wastes. Moreover, the valorization of functional compounds recovered from the fruit and vegetable by-products and wastes is evaluated in detail by emphasizing the type of the by-products/wastes, functional compounds obtained from these by-products/wastes, their extraction conditions and application areas.

Magnesium Binding by Cyberlindnera jadinii Yeast in Media from Potato Wastewater and Glycerol

The aim of this study was to determine the magnesium-binding capacity of Cyberlindnera jadinii yeast in media prepared from potato wastewater and glycerol (after biodiesel production), supplemented with magnesium salt. The research was carried out in two stages. In the first, the ability to binding magnesium by yeast in media supplemented with various doses of this element was tested. In the second stage, after selecting the appropriate dose of magnesium, the culture was carried out in a bioreactor. The composition of the yeast biomass was also analysed in terms of lipids and protein content and amino acid composition. Studies have shown that this type of medium can be used as a culture medium for the growth of C. jadinii yeast. In the first stage of the study, the most magnesium (8.97 mg/gd.m.) was bound by yeast cells after 48 h of cultivation in a medium supplemented with the addition of magnesium at a dose of 2 g/L. In the second stage of the research, the highest magnesium content in the biomass (7.9 mg/gd.m.) was noted after 24 h of cultivation in the same medium. The lipid and protein contents in the biomass obtained after 24 h of cultivation in the bioreactor were 6.35 and 43.73%, respectively. The main fatty acids present in the yeast lipids were oleic acid (59.4%) and linoleic acid (8.6%). Analysis of the amino acid profile of the proteins showed the highest proportions were glutamic acid (13.7%) and aspartic acid (11%).

The ‘Edge Effect’ Phenomenon in Plants: Morphological, Biochemical and Mineral Characteristics of Border Tissues

The ‘edge’ effect is considered one of the fundamental ecological phenomena essential for maintaining ecosystem integrity. The properties of plant outer tissues (root, tuber, bulb and fruit peel, tree and shrub bark, leaf and stem trichomes) mimic to a great extent the ‘edge’ effect properties of different ecosystems, which suggests the possibility of the ‘edge’ effect being applicable to individual plant organisms. The most important characteristics of plant border tissues are intensive oxidant stress, high variability and biodiversity of protection mechanisms and high adsorption capacity. Wide variations in morphological, biochemical and mineral components of border tissues play an important role in the characteristics of plant adaptability values, storage duration of roots, fruit, tubers and bulbs, and the diversity of outer tissue practical application. The significance of outer tissue antioxidant status and the accumulation of polyphenols, essential oil, lipids and minerals, and the artificial improvement of such accumulation is described in connection with plant tolerance to unfavorable environmental conditions. Methods of plant ‘edge’ effect utilization in agricultural crop breeding, production of specific preparations with powerful antioxidant value and green nanoparticle synthesis of different elements have been developed. Extending the ‘edge’ effect phenomenon from ecosystems to individual organisms is of fundamental importance in agriculture, pharmacology, food industry and wastewater treatment processes.

Potato waste as feedstock to produce biohydrogen and organic acids: A comparison of acid and alkaline pretreatments using response surface methodology

The effects of physicochemical pre-treatment were evaluated on hydrogen (H₂) production and organic acids from hydrolyzed potato peel. Central composite design (CCD) and response surface methodology (RSM) were used to evaluate the effects of different substrate concentrations on a wet basis (38.8-81.2 g.L^-1) and hydrolyser ratios (6M NaOH and 30% HCl: 1.6-4.4% v.v^-1; and H₂SO₄: 2.2-7.8% v.v^-1). The experiments were conducted in batch reactors at 37 °C, using a heat-treated microbial consortium. The maximum H₂ production potential (P), lag phase (λ), and maximum H₂ production rate (R_m) were evaluated for untreated and pre-treated potato peel waste. H₂ production was positively influenced under hydrolyzed substrate concentrations ≥75 g.L^-1 in the three CCDs performed. Only the increase in the H₂SO₄ proportions (≥5% v.v^-1) had a negative influence on H₂ production. Increasing the 30% HCl and 6M NaOH proportions did not significantly influence the cumulative H₂ production. The highest hydrogen production was obtained after alkaline pre-treatment by dark fermentation (P: 762.09 mL H₂.L^-1; λ: 14.56 h; R_m: 38.39 mL H₂.L^-1.h^-1). Based on the CCD and RSM, the highest H₂ production (1060.10 mL H₂.L^-1) was observed with 81.2 g.L^-1 hydrolyzed potato peel with 3.0% v.v^-1 of 6M NaOH. The highest yield liquid metabolites were acetic (513.70 mg. g^-1 COD) and butyric acids (491.90 mg. g^-1 COD).

Production and Characterization of Active Bacterial Cellulose Films Obtained from the Fermentation of Wine Bagasse and Discarded Potatoes by Komagateibacter xylinus

Potato waste, such as peels, broken or spoiled potatoes and grape bagasse residues from the winery industry, can be used for the biotechnological production of high-value products. In this study, green, sustainable and highly productive technology was developed for the production of antioxidant bacterial cellulose (BC). The aim of this work was to evaluate the feasibility of a low-cost culture medium based on wine bagasse and potato waste to synthesize BC. Results show that the production of BC by Komagateibacter xylinus in the GP culture medium was five-fold higher than that in the control culture medium, reaching 4.0 g/L BC in 6 days. The compounds of the GP culture medium improved BC production yield. The mechanical, permeability, swelling capacity, antioxidant capacity and optical properties of the BC films from the GP medium were determined. The values obtained for the tensile and puncture properties were 22.77 MPa for tensile strength, 1.65% for elongation at break, 910.46 MPa for Young's modulus, 159.31 g for burst strength and 0.70 mm for distance to burst. The obtained films showed lower permeability values (3.40 × 10^-12 g/m·s·Pa) than those of other polysaccharide-based films. The BC samples showed an outstanding antioxidant capacity (0.31-1.32 mg GAE/g dried film for total phenolic content, %DPPH^• 57.24-78.00% and %ABTS^•+ 89.49-86.94%) and excellent UV-barrier capacity with a transmittance range of 0.02-0.38%. Therefore, a new process for the production of BC films with antioxidant properties was successfully developed.

Novel zero waste tactics for commercial vegetables – recent advances

Commercial vegetables include tomatoes, potatoes, onions, and eggplant due to their surplus production, availability, and affordability. The valorisation of the massive wastage of commercial vegetables and providing a long-term solution has been challenging. The review addresses the implications of biowastes on the environment and fosters the recent investigations into valorising commercial vegetable waste to develop multiple value-added products. It discussed the outcomes of the multiple technologies, majorly on green chemistry extraction, while outlining other methods such as fermentation, enzymatic treatments, 3D printing foods, high-pressure homogenisation, microencapsulation, bio-absorption method, and pyrolysis for their respective vegetable wastes. Agri-residues can be a valuable source for formulating functional ingredients, natural additives, biodiesel, dyes, and animal feed. This comprehensive review proposes a strategy to upcycle low-cost biowaste to boost the economic and ecological benefits. The current review captures the interests and great collaborations between researchers, industrialists, policymakers, waste management bodies, and eco-activists.

Screening and identification of a strain of Aureobasidium pullulans and its application in potato starch industrial waste

Pullulan and melanin have become important secondary metabolites that are now widely studied. In this study, a strain of Aureobasidium pullulans HIT-LCY3^T was used to ferment potato starch industrial waste to produce pullulan and melanin. After optimization, the culture conditions for the fermentation medium were obtained: inoculum age of 48 h, initial pH of 6.0, inoculation quantity of 1.5%, temperature of 26 °C, fermentation time of 5 d and speed of 160 rpm. Under these conditions, the yield of pullulan was 23.47 g/L with a molecular weight (MW) of 1.21 × 10⁶ Da and the yield of melanin was 18.98 g/L. In addition, the adaptive evolution could significantly increase the yield of pullulan and melanin and the air-floating fermenters was more conductive to product accumulation. Through the 5 L small-scale test and 1000 L pilot test, the yield of pullulan reached 16.52 g/L with molecular weight of 0.92 × 10⁶ Da and the yield of melanin was 12.08 g/L at the trial production of 30,000 L. This work could provide strong support for industrial production and new guidance for waste utilization and environmental protection.

Use of apple pomace, glycerine, and potato wastewater for the production of propionic acid and vitamin B12

Abstract

Propionic acid bacteria (PAB) are a source of valuable metabolites, including propionic acid and vitamin B12. Propionic acid, a food preservative, is synthesized from petroleum refining by-products, giving rise to ecological concerns. Due to changing food trends, the demand for vitamin B12 has been expected to increase in the future. Therefore, it is necessary to look for new, alternative methods of obtaining these compounds. This study was conducted with an aim of optimizing the production of PAB metabolites using only residues (apple pomace, waste glycerine, and potato wastewater), without any enzymatic or chemical pretreatment and enrichment. Media consisting of one, two, or three industrial side-streams were used for the production of PAB metabolites. The highest production of propionic acid was observed in the medium containing all three residues (8.15 g/L, yield: 0.48 g/g). In the same medium, the highest production of acetic acid was found — 2.31 g/L (0.13 g/g). The presence of waste glycerine in the media had a positive effect on the efficiency of propionic acid production and P/A ratio. The concentration of vitamin B12 obtained in the wet biomass of Propionibacterium freudenreichii DSM 20271 ranged from 90 to 290 µg/100 g. The highest production of cobalamin was achieved in potato wastewater and apple pomace, which may be a source of the precursors of vitamin B12 — cobalt and riboflavin. The results obtained show both propionic acid and vitamin B12 can be produced in a more sustainable manner through the fermentation of residues which are often not properly managed.

Key points

• The tested strain has been showed metabolic activity in the analyzed industrial side-streams (apple pomace, waste glycerine, potato wastewater).

• All the side-streams were relevant for the production of propinic acid.

• The addition of waste glycerine increases the propionic acid production efficiency and P/A ratio.

• B12 was produced the most in the media containing potato wastewater and apple pomace as dominant ingredients.

Optimization of Monascus purpureus for Natural Food Pigments Production on Potato Wastes and Their Application in Ice Lolly

During potato chips manufacturing, large amounts of wastewater and potato powder wastes are produced. The wastewater obtained at washing after cutting the peeled potatoes into slices was analyzed, and a large quantity of organic compounds and minerals such as starch (1.69%), protein (1.5%), total carbohydrate (4.94%), reducing sugar (0.01%), ash (0.14%), crude fat (0.11%), Ca (28 mg/L), Mg (245 mg/L), Fe (45.5 mg/L), and Zn (6.5 mg/L) were recorded; these wastes could be considered as valuable by-products if used as a fermentation medium to increase the value of the subsequent products and to exceed the cost of reprocessing. In this study, we used wastewater and potato powder wastes as a growth medium for pigment and biomass production by Monascus purpureus (Went NRRL 1992). The response surface methodology was used to optimize total pigment and fungal biomass production. The influence of potato powder waste concentration, fermentation period, and peptone concentration on total pigment and biomass production was investigated using the Box-Behnken design method with 3-factors and 3-levels. The optimal production parameters were potato powder waste concentration of 7.81%, fermentation period of 12.82 days, and peptone concentration of 2.87%, which produced a maximum total pigment of 29.86 AU/ml that include, respectively, a maximum biomass weight of 0.126 g/ml and the yield of pigment of 236.98 AU/g biomass. The pigments produced were used as coloring agents for ice lolly. This study has revealed that the ice lolly preparations supplemented with these pigments received high acceptability. Finally, we recommend using wastewater and potato powder wastes for pigment and biomass production, which could reduce the cost of the pigment production process on an industrial scale in the future.

Low cost nutrient-rich oil palm trunk bagasse hydrolysate for bio-succinic acid production by Actinobacillus succinogenes

Economical source of succinic acid (SA) is most sought-after as a key platform chemical for a wide range of applications. Low-cost production of bio-succinic acid (bio-SA) from a renewable biomass resource i.e., oil palm trunk (OPT) is reported in this paper. Apart from carbon source, nitrogen source and mineral salts are other important nutrients affecting microbial cell growth and bio-SA biosynthesis by Actinobacillus succinogenes 130Z. In order to access and optimize nutrient requirement of the latter two sources, their effects in terms of types and concentrations were investigated. The findings highlighted the importance of selecting proper nitrogen source in A. succinogenes fermentation. The possibility of producing bio-SA from OPT economically can be achieved through minimal supply of 5 g/L yeast extract compared to that generally supplemented 15 g/L with a similar yield (0.47 g/g). In addition, a higher bio-SA yield (0.49 g/g) was achieved without adding mineral salts, which could further reduce fermentation cost. The use of minimally supplemented hydrolysate resulted in 21.1 g/L of bio-SA with a satisfactory yield (0.58 g/g) in a batch bioreactor system with an estimated 56.4% in cost savings. Conclusively, OPT bagasse hydrolysate is a nutrient-rich feedstock that can be practically utilized for bio-SA production.

Influence of potato variety on polyphenol profile composition and glycoalcaloid contents of potato juice

The results of studies published in recent years indicate the broad biological activity of potato juice (PJ), which is a byproduct of the starch production process. Among the most frequently described activities are anti-inflammatory, antioxidant, and cytotoxic effects. Nevertheless, this waste juice is produced by the processing of many varieties of potatoes with different proportions, which does not allow to conclude on the biological activity of individual varieties. This article is a report on the antioxidant activity of PJ from seven selected potato varieties, their profile of polyphenolic compounds, and the content of glycoalkaloids (GAs). The use of similar cultivation conditions allowed to eliminate the influence of environmental factors on the content of the analyzed compounds. The influence of PJ on the growth of probiotic, commensal, and pathogenic bacteria was also assessed. It was shown that the varieties significantly influenced the differences in antioxidant activity as well as the content of GAs, but despite the observed differences, none of them showed antimicrobial activity. Therefore, it can be concluded that an appropriately selected variety will make it possible to obtain PJ that will be characterized by high antioxidant activity and, at the same time, will be safe from the toxicological point of view.

Nutritional Characteristics Assessment of Sunflower Seeds, Oil and Cake. Perspective of Using Sunflower Oilcakes as a Functional Ingredient

Ample amounts of by-products are generated from the oil industry. Among them, sunflower oilcakes have the potential to be used for human consumption, thus achieving the concept of sustainability and circular economy. The study assessed the nutritional composition of sunflower seeds, cold-pressed oil and the remaining press-cakes with the aim of its valorization as a food ingredient. Sunflower oil contains principally oleic (19.81%) and linoleic (64.35%) acids, which cannot be synthetized by humans and need to be assimilated through a diet. Sunflower seeds are very nutritive (33.85% proteins and 65.42% lipids and 18 mineral elements). Due to the rich content of lipids, they are principally used as a source of vegetable oil. Compared to seeds, sunflower oilcakes are richer in fibers (31.88% and 12.64% for samples in form of pellets and cake, respectively) and proteins (20.15% and 21.60%), with a balanced amino acids profile. The remaining oil (15.77% and 14.16%) is abundant in unsaturated fatty acids (95.59% and 92.12%). The comparison between the three products showed the presence of valuable components that makes them suitable for healthy diets with an adequate intake of nutrients and other bioactive compounds with benefic effects.

Potato Juice, a Starch Industry Waste, as a Cost-Effective Medium for the Biosynthesis of Bacterial Cellulose

In this work, we verified the possibility of valorizing a major waste product of the potato starch industry, potato tuber juice (PJ). We obtained a cost-effective, ecological-friendly microbiological medium that yielded bacterial cellulose (BC) with properties equivalent to those from conventional commercial Hestrin–Schramm medium. The BC yield from the PJ medium (>4 g/L) was comparable, despite the lack of any pre-treatment. Likewise, the macro- and microstructure, physicochemical parameters, and chemical composition showed no significant differences between PJ and control BC. Importantly, the BC obtained from PJ was not cytotoxic against fibroblast cell line L929 in vitro and did not contain any hard-to-remove impurities. The PJ-BC soaked with antiseptic exerted a similar antimicrobial effect against Staphylococcus aureus and Pseudomonas aeruginosa as to BC obtained in the conventional medium and supplemented with antiseptic. These are very important aspects from an application standpoint, particularly in biomedicine. Therefore, we conclude that using PJ for BC biosynthesis is a path toward significant valorization of an environmentally problematic waste product of the starch industry, but also toward a significant drop in BC production costs, enabling wider application of this biopolymer in biomedicine.

Fumaric acid production using alternate fermentation mode by immobilized Rhizopus oryzae-a greener production strategy

The current work investigates the impact of using immobilized Rhizopus oryzae NRRL 1526 for bioproduction of fumaric acid using agro-industrial residues as feedstock. This use of agro-industrial residues, a renewable feedstock, for the production of bio-based platform chemical makes the process cost-competitive as well as greener by preventing the release of assimilable organic carbon to the environment, thereby reducing the generation of greenhouse gases. Immobilization of R. oryzae has been proposed previously to alleviate operational difficulties confronted during free mycelial fungal fermentation. To this effect, three synthetic refuse materials namely polystyrene foam, polyester sponge and polyurethane foam were investigated for their suitability towards fumaric acid bioproduction. Polystyrene foam was identified as the most suitable support material for immobilization as well as fumaric acid production. In addition to the considerable reduction in the lag-phase (from 48 to 24 h) the reduction in the size of the support material from cubes of 1 cm to beads of 0.1-0.3 cm led to a 42% improvement in fumaric acid production (27 g/L against 19 g/L). Growing the polystyrene foam bead immobilized R. oryzae on apple pomace ultrafiltration sludge as sole feedstock yielded a final fumaric acid titer of 7.9 g/L whereas free mycelial fermentation yielded 6.3 g/L. Moreover, upon operating the fermentation with intermittent feeding, a three-fold increase (1.7 g/L to 5.1 g/L) in fumaric acid production was obtained upon supplementation of the apple pomace sludge media with molasses, an agro-industrial residue, as feed.

Use of Propionibacterium freudenreichii T82 Strain for Effective Biosynthesis of Propionic Acid and Trehalose in a Medium with Apple Pomace Extract and Potato Wastewater

Propionic acid bacteria are the source of many metabolites, e.g., propionic acid and trehalose. Compared to microbiological synthesis, the production of these metabolites by petrochemical means or enzymatic conversion is more profitable. The components of microbiological media account for a large part of the costs associated with propionic fermentation, due to the high nutritional requirements of Propionibacterium. This problem can be overcome by formulating a medium based on the by-products of technological processes, which can act as nutritional sources and at the same time replace expensive laboratory preparations (e.g., peptone and yeast extract). The metabolic activity of P. freudenreichii was investigated in two different breeding environments: in a medium containing peptone, yeast extract, and biotin, and in a waste-based medium consisting of only apple pomace and potato wastewater. The highest production of propionic acid amounting to 14.54 g/L was obtained in the medium containing apple pomace and pure laboratory supplements with a yield of 0.44 g/g. Importantly, the acid production parameters in the waste medium reached almost the same level (12.71 g/L, 0.42 g/g) as the medium containing pure supplements. Acetic acid synthesis was more efficient in the waste medium; it was also characterized by a higher level of accumulated trehalose (59.8 mg/g d.s.). Thus, the obtained results show that P. freudenreichii bacteria exhibited relatively high metabolic activity in an environment with apple pomace used as a carbon source and potato wastewater used as a nitrogen source. This method of propioniate production could be cheaper and more sustainable than the chemical manner.

Proteins from Agri-Food Industrial Biowastes or Co-Products and Their Applications as Green Materials

A great amount of biowastes, comprising byproducts and biomass wastes, is originated yearly from the agri-food industry. These biowastes are commonly rich in proteins and polysaccharides and are mainly discarded or used for animal feeding. As regulations aim to shift from a fossil-based to a bio-based circular economy model, biowastes are also being employed for producing bio-based materials. This may involve their use in high-value applications and therefore a remarkable revalorization of those resources. The present review summarizes the main sources of protein from biowastes and co-products of the agri-food industry (i.e., wheat gluten, potato, zein, soy, rapeseed, sunflower, protein, casein, whey, blood, gelatin, collagen, keratin, and algae protein concentrates), assessing the bioplastic application (i.e., food packaging and coating, controlled release of active agents, absorbent and superabsorbent materials, agriculture, and scaffolds) for which they have been more extensively produced. The most common wet and dry processes to produce protein-based materials are also described (i.e., compression molding, injection molding, extrusion, 3D-printing, casting, and electrospinning), as well as the main characterization techniques (i.e., mechanical and rheological properties, tensile strength tests, rheological tests, thermal characterization, and optical properties). In this sense, the strategy of producing materials from biowastes to be used in agricultural applications, which converge with the zero-waste approach, seems to be remarkably attractive from a sustainability prospect (including environmental, economic, and social angles). This approach allows envisioning a reduction of some of the impacts along the product life cycle, contributing to tackling the transition toward a circular economy.

Membrane Filtration-Assisted Enzymatic Hydrolysis Affects the Biological Activity of Potato Juice

The results of recently published studies indicate that potato juice is characterized by interesting biological activity that can be particularly useful in the case of gastrointestinal symptoms. Moreover, the studies also described the high nutritional value of its proteins. This article is a report on the impact of the enzymatic hydrolysis of proteins combined with membrane filtration. The obtained potato juice protein hydrolysate (PJPH) and its concentrate (cPJPH) were characterized in terms of their nutritional value and biological activity. The amino acid profile and scoring, the content of mineral compounds, and the antioxidant and in vitro cytotoxic activity were assessed. The study proved that the antioxidant activity of PJPH is higher than that of fresh potato juice, and the cytotoxicity against human gastric carcinoma cell line (Hs 746T), human colon cancer cell line (Caco-2), human colorectal adenocarcinoma cell line (HT-29), and human normal colon mucosa cell line (CCD 841 CoN) showed biological activity specifically targeted against cancer cells. Therefore, it can be concluded that the membrane filtration-assisted enzymatic hydrolysis of potato juice proteins may increase their biological activity and allow for potato juice to be used in the production of medicinal preparations.

Propionic acid production from apple pomace in bioreactor using Propionibacterium freudenreichii: an economic analysis of the process

Propionic acid and its salts are widely used as food and feed preservative. Currently, these compounds are chemically produced, which is more profitable compared to biotechnological production using bacteria of the Propionibacterium genus. Appropriate steps can enable reducing the production costs; for example, cheap industrial byproducts can be used as culture media. One such cost-effective raw material is apple pomace, a low-value byproduct from the food industry. It contains sugars such as glucose and fructose which can serve as potential carbon sources for microorganisms. This paper discusses the possibility of using apple pomace in the production of propionic acid and presents an economic analysis of the production process. The tested strain produced 8.01 g/L of propionic acid (yield 0.40 g/g) and 2.29 g/L of acetic acid (yield 0.11 g/g) from apple pomace extract. The economic analysis showed that the production of 1 kg of propionic acid (considering only waste) from 1000 kg of apple pomace would cost approximately 1.25 USD. The manufacturing cost (consumables, including feedstock, labor, and utilities) would be approximately 2.35 USD/kg, and the total cost including taxes would be approximately 3.05 USD/kg. From the economic point of view, it is necessary to improve the production of propionic acid from apple pomace, to increase the yield of fermentation and thus decrease the total production costs. This can be achieved, for example, using industrial byproducts as nitrogen and vitamin sources, instead of high-cost substrates such as yeast extract or peptone.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-020-02582-x.

Improving the Solubility and Digestibility of Potato Protein with an Online Ultrasound-Assisted PH Shifting Treatment at Medium Temperature

Ultrasonic (US) treatment was combined with pH shifting (pHS) and mild thermal (40 °C) (T40) treatment (US/T40/pHS) to improve the solubility of potato protein. The effects of the ultrasonication frequency, ultrasonication time, and incorporation sequence on the solubility of potato protein were investigated. The results showed that online US/T40/pHS treatment resulted in higher solubility of potato protein and enhanced free amino group release during in vitro digestion. The solubility of potato protein treated with online US/T40/pHS at a mono-frequency of 40 kHz for 15 min increased by 1.73 times compared with the control (p < 0.05). The digestibility rate increased by 16.0% and 30.8% during gastric and intestinal digestion, respectively, compared with the control (p < 0.05). It was demonstrated that online US/T40/pHS treatment significantly changed the secondary and tertiary structures of potato protein according to the results of circular dichroism and internal fluorescence. SDS-PAGE, particle size, and atomic force microscopy (AFM) showed that structural changes led to the formation of large soluble aggregates. The results suggested that the improvement in the solubility and digestibility of potato protein treated with online US/T40/pHS may be due to the formation of large soluble aggregates, which are more hydrophilic and sensitive to digestive enzymes.

The aspects of microbial biomass use in the utilization of selected waste from the agro-food industry

Cellular biomass of microorganisms can be effectively used in the treatment of waste from various branches of the agro-food industry. Urbanization processes and economic development, which have been intensifying in recent decades, lead to the degradation of the natural environment. In the first half of the 20th century, problems related to waste management were not as serious and challenging as they are today. The present situation forces the use of modern technologies and the creation of innovative solutions for environmental protection. Waste of industrial origin are difficult to recycle and require a high financial outlay, while the organic waste of animal and plant origins, such as potato wastewater, whey, lignin, and cellulose, is dominant. In this article, we describe the possibilities of using microorganisms for the utilization of various waste products. A solution to reduce the costs of waste disposal is the use of yeast biomass. Management of waste products using yeast biomass has made it possible to generate new metabolites, such as β-glucans, vitamins, carotenoids, and enzymes, which have a wide range of industrial applications. Exploration and discovery of new areas of applications of yeast, fungal, and bacteria cells can lead to an increase in their effective use in many fields of biotechnology.

Effect of addition of dried potato pulp on selected quality characteristics of shortcrust pastry cookies

Potato pulp is a nuisance waste from the production of potato starch, containing large amounts of dietary fiber; therefore, addition of the pulp to food may have a positive effect on the nutritional value of food products. To increase the amount of dietary fiber, shortcrust pastry cookies were baked by replacing some of the flour (20-100%) with an equivalent amount of dried potato pulp. In all the tested variants, correct confectionery products were obtained. The color of finished product (measured using Konica-Minolta CM-5 spectrophotometer) and mechanical properties of raw dough and baked cookies (subjected to a tensile test, using INSTRON 5544 Tensile Tester) were determined. Furthermore, the samples were subjected to sensory consumer assessment (evaluated on a 7-point hedonic scale). Colorimetric tests of the cookies showed a slight shift in their color from yellow toward green but at the same time lowering its saturation. Strength tests show that only the replacement of more than 40% of flour by the dried pulp resulted in a significant increase in the hardness of baked products. Regarding the tests with consumers, cookies containing up to 40% potato pulp were acceptable. Such a large addition of potato pulp to shortcrust pastry cookies creates new opportunities for this waste management.

Physiological and genome-wide RNA-sequencing analyses identify candidate genes in a nitrogen-use efficient potato cv. Kufri Gaurav

Nitrogen (N) is an important nutrient for plant growth. However, its excess application leads to environmental damage. Hence, improving nitrogen use efficiency (NUE) of plant is one of the plausible options to solve the problems. Aim of this study was to identify candidate genes involved in enhancing NUE in potato cv. Kufri Gaurav (N efficient). Plants were grown in aeroponic with two contrasting N regimes (low N: 0.75 mM, and high N: 7.5 mM). Higher NUE in Kufri Gaurav was observed in low N based on the parameters like NUE, NUpE (N uptake efficiency), NUtE (N utilization efficiency) and AgNUE (agronomic NUE). Further, global gene expression profiles in root, leaf and stolon tissues were analyzed by RNA-sequencing using Ion Proton™ System. Quality data (≥Q20) of 2.04-2.73 Gb per sample were mapped with the potato genome. Statistically significant (P ≤ 0.05) differentially expressed genes (DEGs) were identified such as 176 (up-regulated) and 30 (down-regulated) in leaves, 39 (up-regulated) and 105 (down-regulated) in roots, and 81 (up-regulated) and 694 (down-regulated) in stolons. The gene ontology (GO) terms like metabolic process, cellular process and catalytic activity were predominant. Our RT-qPCR analysis confirmed the gene expression profiles of RNA-seq. Overall, we identified candidate genes associated with improving NUE such as superoxide dismutase, GDSL esterase lipase, probable phosphatase 2C, high affinity nitrate transporters, sugar transporter, proline rich proteins, transcription factors (VQ motif, SPX domain, bHLH) etc. Our findings suggest that these candidate genes probably play crucial roles in enhancing NUE in potato.