One pot clarification and debittering of grapefruit juice using co-immobilized enzymes@chitosanMNPs

Immobilized enzymes: exploring its potential in food industry applications

The global demand for nutritious, longer-lasting food has spurred the food industry to seek eco-friendly solutions. Enzymes play a vital role in enhancing food quality by improving flavor, texture, and nutritional content. However, challenges like rapid deactivation and non-recoverability of free enzymes are addressed by immobilized enzymes, which enhance efficiency, quality, and sustainability in food processing. Immobilization methods include adsorption, covalent binding, entrapment, encapsulation and cross-liked enzyme aggregates, which enhancing their stability, reusability, and catalytic efficiency. Immobilization of enzyme such as pectinase, amylase, naringinase, cellulase, lactase, glucoamylase, xylanase, invertase, lipase, phytase, and protease have been utilized in fruit, vegetable, baking, dairy, brewing, and feed process due to their high thermostability, improved shelf life, food quality and safety. The catalytic efficiency of immobilized enzymes in detecting and quantifying various food components, contaminants, and quality indicators, also developed functional foods with nutraceuticals benefits, include prebiotic juices, lactose-free dairy products, poly unsaturated fatty acids rich foods, low-calorie sweeteners, fortified food and bioactive peptides.

Graphical abstract

Magnetic Janus SiO2 nanoparticles immobilized protease mutant T70I as a novel clarification agent for juice processing

The juice processing industry offers several benefits, including promoting health and wellness through the delivery of beverages rich in nutrients. Nonetheless, the industry encounters significant challenges regarding new technologies for processing and preservation given that they can be costly and labor-intensive. In this study, magnetic Janus silica (SiO2) nanoparticle which offers multifunctionality and high stability was synthesized and subsequently immobilized with a protease mutant T70I (T70I@MSNs) to serve as a clarifying agent in juice. The optimal conditions for the protease immobilized with SiO2 nanoparticles showed superior tolerance and stability at pH 5 and 65 °C. Box-Behnken Design revealed optimizing conditions of 60 min, 50 °C and 0.2 % enzyme concentration which significantly influenced the clarification of the juice samples. Immobilized T70I@MSNs decreased >70 % of juice turbidity while maintaining about 78 % of enzyme activity after 7 consecutive cycles of reuse. Notably, T70I@MSN treatment enhanced certain volatile components by increasing alcohol and ester production, while changes in surface microstructure and functional groups were observed. This study highlights the significant improvement of magnetic Janus SiO2 nanoparticles immobilized proteases in the clarification of juice against haze and undesirable properties, thereby offering a notable contribution to the juice processing industry.

Pectinase immobilized on magnetic nanoparticles coated with alginate for pectin hydrolysis in guava juice assisted by a stirred electromagnetic reactor

Aspergillus aculeatus pectinase was immobilized on magnetic nanoparticles coated with calcium alginate for pectin hydrolysis in guava juice by a stirred electromagnetic reactor (SER). The average crystallite size estimated by the Scherrer formula was 33.7 nm. The reaction rate in SER (701.7 U/mL) was almost twice that of the static process (362.5 U/mL). Both processes displayed a sigmoidal trend with positive cooperativity (n) of 5 and 4, respectively. Both free and immobilized pectinase showed great performance in the pH range of 4.0-7.0. After immobilization, pectinase acted optimally at 50 °C. Pectin hydrolysis was performed for over 10 successive cycles in SER losing only 30% of its initial activity. Thermodynamic activation parameters of the reaction revealed higher spontaneity and efficiency when hydrolysis was performed in SER. Pectin hydrolysis in guava juice displayed 41% turbidity and 85.5% viscosity reduction. The electromagnetic reactor displayed great potential for performing hydrolysis of pectin in guava juice. The biocatalyst showed good features for further applications in food industries.

Evaluation of free and immobilized cellulase on chitosan-modified magnetic nanoparticles for saccharification of sorghum residue

Enzymatic hydrolysis plays a pivotal role in transforming lignocellulosic biomass. Addressing alternate techniques to optimize the utilization of cellulolytic enzymes is one strategy to improve its efficiency and lower process costs. Cellulases are highly specific and environmentally benign biocatalysts that break down intricate polysaccharides into simple forms of sugars. In contrast to the most difficult and time-consuming enzyme immobilization processes, in this research, we studied simple, mild, and successful techniques for immobilization of pure cellulase on magnetic nanocomposites using glutaraldehyde as a linker and used in the application of sorghum residue biomass. Fe3O4 nanoparticles were coated with chitosan from the co-precipitation method, which served as an enzyme carrier. The nanoparticles were observed under XRD, Zeta Potential, FESEM, VSM, and FTIR. The size morphology results presented that the Cs@Fe3O4 have 42.2 nm, while bare nanoparticles (Fe3O4) have 31.2 nm in size. The pure cellulase reaches to 98.07% of loading efficiency and 71.67% of recovery activity at optimal conditions. Moreover, immobilized enzyme's pH stability, thermostability, and temperature tolerance were investigated at suitable conditions. The kinetic parameters of free and immobilized enzyme were estimated as Vmax; 29 ± 1.51 and 27.03 ± 2.02 µmol min-1 mg-1, Km; 4.7 ± 0.49 mM and 2.569 ± 0.522 mM and Kcat; 0.13 s-1, and 0.89 s-1. Sorghum residue was subjected to 2% NaOH pre-treatment at 50 ℃. Pre-treated biomass contains cellulose of 64.8%, used as a raw material to evaluate the efficiency of reducing sugar during hydrolysis and saccharification of free and immobilized cellulase, which found maximum concentration of glucose 5.42 g/L and 5.12 g/L on 72 h. Thus, our study verifies the use of immobilized pure cellulase to successfully hydrolyze raw material, which is a significant advancement in lignocellulosic biorefineries and the reusability of enzymes.

Development of a novel magnetic metal-organic framework for the immobilization of short-chain dehydrogenase for the asymmetric reduction of pro-chiral ketone

Short-chain dehydrogenase/reductase (SDR) acts as a biocatalyst in the synthesis of chiral alcohols with high optical purity. Herein, we achieved immobilization via crosslinking on novel magnetic metal-organic framework nanoparticles with a three-layer shell structure (Fe3O4@PDA@Cu (PABA)). The results of scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectroscopy confirmed the morphology and cross-linking property of immobilized SDR, which was more durable, stable, and reusable and exhibited better kinetic performance than free enzyme. The SDR and glucose dehydrogenase (GDH) were co-immobilized and then used for the asymmetric reduction of COBE and ethyl 2-oxo-4-phenylbutanoate (OPBE). These finding suggest that enzymes immobilized on novel MOF nanoparticles can serve as promising biocatalysts for asymmetric reduction prochiral ketones into chiral alcohols.

Optimization of limonin invertase production by scaling up Aspergillus tubingensis UA13 fermentation to a 5-l scale

The enzymatic approach is a highly effective and the major scientific method to eliminating bitter components in citrus-derived products nowadays. Microbial production of limonin invertase stands out due to its pivotal role in the removal of the bitter substance, limonin. The optimization of fermentation parameters and the study of scale-up fermentation are imperative for product commercialization. In this study, we focused on optimizing stirring speed, fermentation temperature, and initial pH to enhance the growth and limonin invertase production by the Aspergillus tabin strain UA13 in a 5-l stirred-tank bioreactor. Our results revealed the following optimal parameters are: a stirring speed of 300 rpm, a fermentation temperature of 35°C and a pH 5.0. Under these optimized conditions, the limonin invertase activity reached its peak at 63.38 U ml-1, representing a 1.67-fold increase compared to the unoptimized conditions (38.10 U ml-1), while also reducing the fermentation duration by 12 h. Furthermore, our research demonstrated that limonin invertase effectively hydrolyze limonin in grapefruit juice, reducing its content from 13.28 to 2.14 μg ml-1, as determined by HPLC, resulting in a 6.21-fold reduction of the bitter substance.

Formation and detection of biocoronas in the food industry and their fate in the human body

The rapid advancement of nanotechnology has opened up new avenues for applications in all stages of the food industry. Over the past decade, extensive research has emphasized that when nanoparticles (NPs) enter organisms, they spontaneously adsorbed biomolecules, leading to the formation of biocorona. This paper provided a detailed review of the process of biocorona formation in the food industry, including their classification and influencing factors. Additionally, various characterization methods to investigated the morphology and structure of biocoronas were introduced. As a real state of food industry nanoparticles in biological environments, the biocorona causes structural transformations of biomolecules bound to NPs, thus affecting their fate in the body. It can either promote or inhibit enzyme activity in the human environment, and may also positively or negatively affect the cellular uptake and toxicity of NPs. Since NPs present in the food industry will inevitably enter the human body, further investigations on biocoronas will offer valuable insights and perspectives on the safety of incorporating more NPs into the food industry.

Nanocatalytic performance of pectinase immobilized over in situ prepared magnetic nanoparticles

Immobilization of enzymes is one of the protein engineering methods used to improve their thermal and long-term stabilities. Immobilized pectinase has become an essential biocatalyst for optimization in the food processing industry. Herein, nanostructured magnetic nanoparticles were prepared in situ for use as supports to immobilize pectinase. The structural, morphological, optical and magnetic features and the chemical compositions of the nanoparticles were characterized. Nanoparticle agglomeration and low porosity were observed due to the synthetic conditions. These nanoparticles exhibited superparamagnetic behavior, which is desirable for biotechnological applications. The maximum retention rate for the enzyme was observed at pH 4.5 with a value of 1179.3 U/mgNP (units per milligram of nanoparticle), which was equivalent to a 65.6% efficiency. The free and immobilized pectinase were affected by the pH and temperature. The long-term instability caused 40% and 32% decreases in the specific activities of the free and immobilized pectinase, respectively. The effects of immobilization were analyzed with kinetic and thermodynamic studies. These results indicated a significant affinity for the substrate, a decreased reaction rate, and improved thermal stability of the immobilized pectinase. The reusability of the immobilized pectinase was preserved effectively during cycling, with only a 21.2% decrease in activity observed from the first to the last use. Therefore, alternative magnetic nanoparticles are presented for immobilizing and maintaining the thermostability of pectinase.

Non-thermal, energy efficient hydrodynamic cavitation for food processing, process intensification and extraction of natural bioactives: A review

Hydrodynamic cavitation (HC) is the process of bubbles formation, expansion, and violent collapse, which results in the generation of high pressures in the order of 100-5000 bar and temperatures in the range of 727-9727 °C for just a fraction of seconds. Increasing consumer demand for high-quality foods with higher nutritive values and fresh-like sensory attributes, food processors, scientists, and process engineers are pushed to develop innovative and effective non-thermal methods as an alternative to conventional heat treatments. Hydrodynamic cavitation can play a significant role in non-thermal food processing as it has the potential to destroy microbes and reduce enzyme activity while retaining essential nutritional and physicochemical properties. As hydrodynamic cavitation occurs in a flowing liquid, there is a decrease in local pressure followed by its recovery; hence it can be used for liquid foods. It can also be used to create stable emulsions and homogenize food constituents. Moreover, this technology can extract food constituents such as polyphenols, essential oils, pigments, etc., via biomass pretreatment, cell disruption for selective enzyme release, waste valorization, and beer brewing. Other applications related to food production include water treatment, biodiesel, and biogas production. The present review discusses the application of HC in the preservation, processing, and quality improvement of food and other related applications. The reviewed examples in this paper demonstrate the potential of hydrodynamic cavitation with further expansion toward the scaling up, which looks at commercialization as a driving force.

Application of functionalized chitosan in food: A review

Environmental and sustainability issues have received increasing attention in recent years. As a natural biopolymer, chitosan has been developed as a sustainable alternative to traditional chemicals such as food preservation, food processing, food packaging, and food additives due to its abundant functional groups and excellent biological functions. This review analyzes and summarizes the unique properties of chitosan, with a particular focus on the mechanism of action for its antibacterial and antioxidant properties. This provides a lot of information for the preparation and application of chitosan-based antibacterial and antioxidant composites. In addition, chitosan is modified by physical, chemical and biological modifications to obtain a variety of functionalized chitosan-based materials. The modification not only improves the physicochemical properties of chitosan, but also enables it to have different functions and effects, showing promising applications in multifunctional fields such as food processing, food packaging, and food ingredients. In the current review, applications, challenges, and future perspectives of functionalized chitosan in food will be discussed.

Biotechnological advancements towards water, food and medical healthcare: A review

The global health status is highly affected by the growing pace of urbanization, new lifestyles, climate changes, and resource exploitation. Modern technologies pave a promising way to deal with severe concerns toward sustainable development. Herein, we provided a comprehensive review of some popular biotechnological advancements regarding the progress achieved in water, food, and medicine, as the most substantial fields related to public health. The emergence of novel organic/inorganic materials has brought about significant improvement in conventional water treatment techniques, anti-fouling approaches, anti-microbial agents, food processing, biosensors, drug delivery systems, and implants. Particularly, a growing interest has been devoted to nanomaterials and their application for developing novel structures or improving the characteristics of standard components. Also, bioinspired materials have been widely used to improve the performance, efficiency, accuracy, stability, safety, and cost-effectiveness of traditional systems. On the other side, the fabrication of innovative devices for precisely monitoring and managing various ecosystem and human health issues is of great importance. Above all, exceptional advancements in designing ion-selective electrodes (ISEs), microelectromechanical systems (MEMs), and implantable medical devices have altered the future landscape of environmental and biomedical research. This review paper aimed to shed light on the wide-ranging materials and devices that have been developed for health applications and mainly focused on the impact of nanotechnology in this field.

Coimmobilized enzymes as versatile biocatalytic tools for biomass valorization and remediation of environmental contaminants - A review

Due to stringent regulatory norms, waste processing faces confrontations and challenges in adapting technology for effective management through a convenient and economical system. At the global level, attempts are underway to achieve a green and sustainable treatment for the valorization of lignocellulosic biomass as well as organic contaminants in wastewater. Enzymatic treatment in the environmental aspect thrived on being the promising rapid strategy that appeased the aforementioned predicament. On that account, coimmobilization of various enzymes on single support enhances the catalytic activity ensuing operational stability with industrial applications. This review pivoted towards the coimmobilization of enzymes on diverse supports and their applications in biomass conversion to industrial value-added products and removal of contaminants in wastewater. The limelight of this study chronicles the unique breakthroughs in biotechnology for the production of reusable biocatalysts, which inculcating various enzymes towards the scope of environment application.

Enzymes-Assisted Extraction of Plants for Sustainable and Functional Applications

The scientific community and industrial companies have discovered significant enzyme applications to plant material. This rise imparts to changing consumers' demands while searching for 'clean label' food products, boosting the immune system, uprising resistance to bacterial and fungal diseases, and climate change challenges. First, enzymes were used for enhancing production yield with mild and not hazardous applications. However, enzyme specificity, activity, plant origin and characteristics, ratio, and extraction conditions differ depending on the goal. As a result, researchers have gained interest in enzymes' ability to cleave specific bonds of macroelements and release bioactive compounds by enhancing value and creating novel derivatives in plant extracts. The extract is enriched with reducing sugars, phenolic content, and peptides by disrupting lignocellulose and releasing compounds from the cell wall and cytosolic. Nonetheless, depolymerizing carbohydrates and using specific enzymes form and release various saccharides lengths. The latest studies show that oligosaccharides released and formed by enzymes have a high potential to be slowly digestible starches (SDS) and possibly be labeled as prebiotics. Additionally, they excel in new technological, organoleptic, and physicochemical properties. Released novel derivatives and phenolic compounds have a significant role in human and animal health and gut-microbiota interactions, affecting many metabolic pathways. The latest studies have contributed to enzyme-modified extracts and products used for functional, fermented products development and sustainable processes: in particular, nanocellulose, nanocrystals, nanoparticles green synthesis with drug delivery, wound healing, and antimicrobial properties. Even so, enzymes' incorporation into processes has limitations and is regulated by national and international levels.

Removal of difenoconazole and nitenpyram by composite calcium alginate beads during apple juice clarification

A novel genipin crosslinked calcium alginate/chitosan/polydopamine composite beads (g-Alg/CS/PDA) was synthesized for the removal of residual difenoconazole and nitenpyram during the clarification of apple juice. The composite beads with low potential health risks for all of the main materials were natural, green and biocompatible. Since g-Alg/CS/PDA can both clarify and adsorb, pesticide residues could be removed during the clarification of juice without additional steps. The g-Alg/CS/PDA beads were characterized, and the adsorption parameters, including the pesticide residue levels, adsorption time, pH, ionic strength, fructose concentration and adsorbent dose, were optimized. The adsorption data were fitted to the Freundlich isotherm model (R² = 0.9604, 0.9625) and the pseudo-second-order kinetic model (R² = 0.9993, 0.9999). The results indicated that the adsorption behavior of beads was heterogeneous. Moreover, the rate was controlled by several factors. The adsorption mechanism of two pesticides was also discussed. Hydrophobic and π-π conjugation interactions played a dominant role for the adsorption of difenoconazole, while hydrogen bonding and electrostatic interactions were the main factors for nitenpyram.

Preparation of regenerable magnetic nanoparticles for cellulase immobilization: Improvement of enzymatic activity and stability

To obtain regenerable magnetic nanoparticles, triethoxy(3-isocyanatopropyl)silane and iminodiacetic acid (IZ) were used as the starting material and immobilized on Fe₃ O₄ nanoparticles. Copper ions (Cu²⁺ ions) were loaded on the Fe-IZ nanoparticles and used for cellulase immobilization. The support was characterized by spectroscopic methods (FTIR, NMR) and thermogravimetric analysis, transmission electron microscopy, scanning electron microscope, X-ray diffraction, energy dispersive X-ray analysis, and vibrating sample magnetometer techniques. As a result of experiments, the amount of protein bound to immobilized cellulase (Fe-IZ-Cu-E) and cellulase activity was found to be 33.1 mg/g and 154 U/g at pH 5, 50°C, for 3 h. The results indicated that the free cellulase had kept only 50% of its activity after 2 h, while the Fe-IZ-Cu-E was observed to be around 77%, at 60°C. It was found that the immobilized cellulase maintained 93% of its initial catalytic activity after its sixth use. Furthermore, the Fe-IZ-Cu-E retained about 75% of its initial activity after 28 days of storage. To reuse the support material (Fe-IZ-Cu), it was regenerated by thorough washing with ammonia or imidazole.