Cauliflower waste utilization for sustainable biobutanol production: revelation of drying kinetics and bioprocess development

Exploring the environmental and economic impact of fruits and vegetable loss quantification in the food industry

Population growth has stimulated rising demand for agro-food products and economic activity for many years, negatively impacting the ecosystem and non-renewable resource consumption. Algeria confronts the monumental challenge of effectively choosing how to nourish everyone on a more congested globe. However, food loss is a significant issue that worsens as Algerians' population expands and food consumption increases. In Algeria, food production and processing of food items, which include fruits, vegetables, and cereals, generate a considerable amount of by-products, with no commercial exploitation and a negative environmental impact, generating enormous socioeconomic problems. These by-products are essential sources of products with high levels of added value that can be applied in different sectors. They have no studies to measure the scope of food loss in the Algerian food industry. In this background, our research aims to quantify the loss in the Algerian food industry generated by the transformation of various agricultural products, directly affecting the economy and food availability for the population. The research utilizes a mixed methods approach, including coefficients, production statistics transformed, and data analysis; the findings reveal that a significant portion of fruits and vegetables are lost in the Algerian food industry, suggesting that minimizing food loss can help companies minimize costs and mitigate the adverse environmental effects of food production. Finally, the study proposes practical options to minimize food loss to create a long-term food system in Algeria.

Compositional profiling and sensory analysis of cauliflower by-products-enriched muffins

Cauliflower (Brassica oleracea var. botrytis) by-products (leaves, stems, stalks) (CBP) were successfully utilized in muffins as a model system and their feasibility of incorporation was investigated. CBP powder-based muffin formulations were made by the progressive replacement of wheat flour (WF) with 10%, 20%, and 30% of CBP. The physicochemical, pasting properties, antioxidant potential, textural characteristics, and sensorial attributes were analyzed. Substitution of CBP significantly (p < .05) resulted in an upsurge in crude protein, crude fiber, minerals, total phenolics, and total flavonoid contents, as well as total antioxidant activity values of muffins. The pasting properties were influenced by monitoring an increase in peak, breakdown, final, and setback viscosities. Although the addition of an increasing amount of CBP improved the nutritional characteristics, however, the increased level of replacement (>10%) had significant adverse effects on baking and physical characteristics. The specific loaf volume of the developed muffins decreased the crumb color which became darker, and enriched muffins were hardened in texture. Furthermore, sensory evaluation confirmed the positive effects of CBP incorporation only up to 10%. Overall, present results highlighted that supplementation of wheat muffins with 10% CBP is a beneficial approach to enrich them with nutrients and intensify their antioxidant potential.

Byproducts of Globe Artichoke and Cauliflower Production as a New Source of Bioactive Compounds in the Green Economy Perspective: An NMR Study

The recovery of bioactive compounds from crop byproducts leads to a new perspective way of waste reutilization as a part of the circular economy. The present study aimed at an exhaustive metabolite profile characterization of globe artichoke and cauliflower byproducts (leaves, stalks, and florets for cauliflower only) as a prerequisite for their valorization and future implementations. The metabolite profile of aqueous and organic extracts of byproducts was analyzed using the NMR-based metabolomics approach. Free amino acids, organic acids, sugars, polyols, polyphenols, amines, glucosinolates, fatty acids, phospho- and galactolipids, sterols, and sesquiterpene lactones were identified and quantified. In particular, globe artichoke byproducts are a source of health-beneficial compounds including chiro-inositol (up to 10.1 mg/g), scyllo-inositol (up to 1.8 mg/g), sesquiterpene lactones (cynaropicrin, grosheimin, dehydrocynaropicrin, up to 45.5 mg/g in total), inulins, and chlorogenic acid (up to 7.5 mg/g), whereas cauliflower byproducts enclose bioactive sulfur-containing compounds S-methyl-L-cysteine S-oxide (methiin, up to 20.7 mg/g) and glucosinolates. A variable content of all metabolites was observed depending on the crop type (globe artichoke vs. cauliflower) and the plant part (leaves vs. stalks). The results here reported can be potentially used in different ways, including the formulation of new plant biostimulants and food supplements.

Cauliflower by-products as functional ingredient in bakery foods: Fortification of pizza with glucosinolates, carotenoids and phytosterols

Industrial cauliflower by-products still represent a no-value food waste, even though they are rich in bioactive compounds. With the aim of valorizing them, optimized special flours rich in glucobrassicin, lutein, β-carotene, and β-sitosterol obtained from leaves, orange and violet stalks were used at 10 and 30% w/w in the formulation of functional leavened bakery. For the first time, the effect of bioactive compounds enrichment in pizza products as well as the rheological properties were evaluated. As results, pizza making process affected the recovery of the bioactive compounds. The recovery of glucobrassicin and carotenoids in pizza depended on the aerial part of cauliflower. Pizza with violet stalks was the richest in glucobrassicin, providing 8.4 mg per portion (200 g). Pizza with leaves showed the highest carotenoid content with a 90% of recovery rate while pizza with orange stalks provided up to 5.8% of the phytosterols health claim requirement. All 10% enriched pizzas revealed viscoelastic and springiness properties similar to the control, contrary to 30% fortification level. Therefore, the use of 10% special flour in pizza should meet both technological industrial processing and consumer acceptance. Orange stalks are the most promising ingredients for high levels of fortification in pizzas.

Enhancement of Bioactive Constituents in Fresh Cauliflower By-Products in Challenging Climate Conditions

In order to mitigate the detrimental impact that climate change is having on plants, the study of new practices that allow for the reduction of such effects has become imperative. In addition, the revaluation of the promotion of healthy plant by-products has also markedly increased in importance in recent years. In this work, the modifications in biomass and some antioxidant compounds of cauliflower by-products treated with putrescine under extreme temperatures in two different CO₂ scenarios (the control (400 ppm) and a high concentration of CO₂ (1000 ppm)) were studied. Additionally, the compositions of inner and outer leaves were also compared. According to results found in this work, cauliflower grown under elevated CO₂ and treated with putrescine (2.5 mM) prior to heat stress showed the highest biomass accumulation (20%) compared to the control. Moreover, in the outer leaves from cauliflower grown under elevated CO₂ and treated with putrescine prior to high temperature exposure, the highest biosynthesis of sugars (20%) was recorded. Although cauliflower by-products turned out to be rich in polyamines (208.6 nmoles g⁻¹ fresh weight (FW) and 124.3 nmoles g⁻¹ FW for outer and inner leaves, respectively) and phenolic compounds (1070.2 mg gallic acid equivalents ( (GAE) 100 g⁻¹ FW in outer leaves and 772.0 mg GAE 100 g⁻¹ FW in inner leaves), it was the outer leaves that after applying the new strategy showed the greatest increase in polyamines (68%) and phenolic compounds (39%), obtaining here the highest increase in antioxidant activity (3%). Thus, they should no longer be regarded as mere by-products and should be used for pharmaceutical or nutraceutical purposes. The novel strategy presented in this work may allow us to take advantage of both the continued increase in CO₂ and heat waves that are becoming more frequent.

Studies on production and evaluation of biopigment and synthetic dye decolorization capacity of laccase produced by A. oryzae cultivated on agro-waste

The present study investigated the screening of mono and co-culture fungal cultivations for laccase production using extracted lignin as the substrate obtained from cauliflower wastes by two different pretreatment methods. Amongst mono and mixed culture fungal cultivations, monoculture of Aspergillus oryzae exhibited the highest enzymatic activity of 29.7 ± 0.6 U mL^-1 under submerged conditions and using alkali extracted lignin as substrate. Under the optimal conditions (pH 4.5, 30 °C, 12 days, 1% (w/v) lignin and 0.5 mM Cu²⁺ concentration) the maximum laccase activity was estimated to be 41.3 ± 2.8 U mL^-1 and production yield of 153.3 ± 2.4 mg L^-1. Maximum decolorization of pigment extracted from Aspergillus heteromorphus CBS 117.55 cultivated culture media was achieved by administration of 40 U g^-1 of crude enzyme concentration. Thermal and pH stability of crude laccase was observed over wide ranges. The dye decolorization efficiency of crude A. oryzae laccase was studied and Congo Red exhibited maximum decolorization percentage (64 ± 1.3%) at 15 µM, 50 °C and pH 4.5. The kinetic study of different dye (Congo Red) concentrations obtained V_max and K_m values of 0.123 × 10^-3 M and 0.724 mol L^-1 min^-1, respectively.

Valorization of Agri-Food Wastes as Sustainable Eco-Materials for Wastewater Treatment: Current State and New Perspectives

The paper addresses environmental protection by valorizing an important agri-food waste category, namely fruit and vegetables with focusing on the main characteristics regarding consumption, waste quantities, and ways for valorizing these materials. Thus, vast research was undertaken in order to emphasize the main commodities and their potential application as adsorbents for organic and inorganic pollutants. The main methods or treatment techniques applied for the valorization of eco-materials as adsorbents were presented and the principal efficiency results were indicated. The advantages and disadvantages of using these eco-materials as adsorbents in wastewater treatment were revealed and future recommendations were established. According to the international statistics, the most purchased and consumed five commodities were studied regarding waste generations as potential conversion into eco-materials with an adsorbent role for water pollutants. Thus, the performances for adsorbents based on fruit wastes (such as citrus, banana, apples, grapes, mango) and vegetable wastes (such as potatoes, tomatoes, cabbage, carrots, cauliflower, and/or broccoli) were studied and highlighted in this research.

The Effect of Foliar Putrescine Application, Ammonium Exposure, and Heat Stress on Antioxidant Compounds in Cauliflower Waste

This work has been focused on the study of how we can affect the short heat stress on the bioactive compounds content. Some recent investigations have observed that management of nitrogen fertilization can alleviate short-term heat effects on plants. Additionally, the short-term heat stress can be also ameliorated by using putrescine, a polyamine, due to its crucial role in the adaptation of plants to heat stress Therefore, different NO₃⁻/NH₄⁺ ratios and a foliar putrescine treatment have been used in order to increase tolerance to thermal stress in order to take advantage of the more frequent and intense heat waves and make this crop more sustainable. So, other objective of this work is to make the cauliflower waste more attractive for nutraceutical and pharmaceutical preparations. Thus, the effect of a thermal stress combined with a 50:50 NO₃⁻/NH₄⁺ ratio in the nutrient solution, and the foliar application of 2.5 mM putrescine increased in the content of various sugars (inositol, glucose, and fructose), total phenolic compounds and polyamines, as well as in the antioxidant activity. The greatest accumulation of these compounds was observed in young leaves. Our results show from a physiological and agronomic point of view, that the foliar application of putrescine and the 50:50 NO₃⁻/NH₄⁺ treatment managed to alleviate the negative effects of the abiotic stress suffered at high temperature, yielding plants with higher antioxidant compounds content.

Effects of Different Nitrogen Forms and Exogenous Application of Putrescine on Heat Stress of Cauliflower: Photosynthetic Gas Exchange, Mineral Concentration and Lipid Peroxidation

This study examines the effect of the exogenous application of polyamine putrescine together with the application of different ratios of nitrate/ammonium (NO₃⁻/NH₄⁺), on the physiology of cauliflower subjected to heat stress. The 50:50 NO₃⁻/NH₄⁺ ratio was the best ratio against heat stress. As a result of the joint application of these compounds, a higher photosynthetic rate, a higher accumulation of both photosynthesis-related compounds and pigments, total proteins, and a change in the status of nutrients were obtained. Particularly, the decrease in content of calcium, chloride and sulphate in plants under heat stress is ameliorated by the ammonium effect. Additionally, it is important to highlight that cauliflower waste contains a higher content of mineral nutrients than floret cauliflower. These effects were more marked in young leaves. Furthermore, a synergistic effect for coping with heat stress between the polyamine and the nutritional treatment was observed. For this, both the application of putrescine and the feeding of plants with a 50:50 NO₃⁻/NH₄⁺ ratio before heat stress is proposed for the first time as an agricultural practice for increasing the thermotolerance of cauliflower cv Moonshine. On the other hand, due to the lower lipid peroxidation rate obtained in cauliflower leaves, these plants could be used for health purposes as ointments or other nutraceutical products, making the cultivation of this kind of cruciferous more sustainable.

Dietary Fiber from Underutilized Plant Resources—A Positive Approach for Valorization of Fruit and Vegetable Wastes

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.

Effect of pretreatment with organic solvent on enzymatic digestibility of cauliflower wastes

The present study investigated the operational conditions for different pretreatment approaches and subsequent enzymatic hydrolysis of cauliflower wastes (stalk and leaf) for better release of fermentable sugars. The structural analysis of raw and pretreated lignocellulosic biomasses was investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transforms infrared (FTIR) analysis. Results demonstrated that the highest cellulose conversion rate and removal of most of the hemicellulose and lignin were obtained with organosolvent pretreatment. Using methanol in presence of sodium (Na) acetate was most effective in delignification of cauliflower wastes. In the present study, methanol (100% v/v) in presence of 0.1 M Na-acetate at 121 °C for 45 and 60 min for stalk and leaf, respectively, gave maximum reducing sugar yield. Response surface methodology was used to optimize different process parameters for enzymatic saccharification using microbial cellulase and xylanase. The optimum operation condition of enzymatic hydrolysis of organosolvent pretreated cauliflower wastes were substrate loading (2.5% w/v for both stalk and leaf), enzyme loading (15 and 10 U/g for stalk and leaf, respectively), pH (4.46 and 5.48 for stalk and leaf, respectively), at 60 °C and for 180 min.

Role of Trace Elements as Cofactor: An Efficient Strategy toward Enhanced Biobutanol Production

Metabolic engineering has the potential to steadily enhance product titers by inducing changes in metabolism. Especially, availability of cofactors plays a crucial role in improving efficacy of product conversion. Hence, the effect of certain trace elements was studied individually or in combinations, to enhance butanol flux during its biological production. Interestingly, nickel chloride (100 mg L^-1) and sodium selenite (1 mg L^-1) showed a nearly 2-fold increase in solvent titer, achieving 16.13 ± 0.24 and 12.88 ± 0.36 g L^-1 total solvents with yields of 0.30 and 0.33 g g^-1, respectively. Subsequently, the addition time (screened entities) was optimized (8 h) to further increase solvent production up to 18.17 ± 0.19 and 15.5 ± 0.13 g L^-1 by using nickel and selenite, respectively. A significant upsurge in butanol dehydrogenase (BDH) levels was observed, which reflected in improved solvent productions. Additionally, a three-dimensional structure of BDH was also constructed using homology modeling and subsequently docked with substrate, cofactor, and metal ion to investigate proper orientation and molecular interactions.