Modelling temperature and pH dependence of lipase and peroxidase activity in Turkish hazelnuts

Preparation and characterization of cellulose nanofiber cryogels as oil absorbents and enzymatic lipolysis scaffolds

Cellulose nanofiber (CNF) materials have received much attention as sustainable "green" materials with high mechanical properties. Their application in oil absorption and enzymatic lipolysis makes them further attractive from the perspective of environmental issues including marine pollution preservation. Herein, we prepared CNF cryogels with various surface properties, evaluated their capacities as oil absorbents and applied them as lipase-lipolysis scaffolds. Their obtained cryogels consisted of various modified CNFs and their structure and properties were investigated. Moreover, lipase-supported CNF cryogels were prepared for enzymatic lipolysis. The cryogels of protonated TEMPO-oxidized CNF showed the highest absorption capacity for olive oil, while all the CNF cryogels possessed similar absorption abilities towards water. In enzymatic lipolysis with lipase, the TEMPO-oxidized CNF (TOCN-Na⁺) cryogel showed the highest specific activity. The specific activities of lipase in TOCN-Na⁺ cryogels remained unchanged after being stored at 40 °C for 3 days.

Effect of Roasting and Storage on the Formation of Maillard Reaction and Sugar Degradation Products in Hazelnuts ( Corylus avellana L.)

This study investigated the effect of roasting (150 °C for 30 min) and storage (12 months at 4 °C, 25 °C, and 25 °C in vacuum package), conditions of which are generally applied in the industry and markets, on the formation of Maillard reaction and sugar degradation products, namely dicarbonyl compounds, 5-hydroxymethylfurfural, N-ε-fructosyllysine, and N-ε-carboxymethyllysine in Tombul and Levant hazelnuts. Roasting increased all dicarbonyl compounds significantly ( p < 0.05). The concentration of methylglyoxal was the highest while 1-deoxyglucosone was the lowest in roasted hazelnuts. 5-Hydroxymethylfurfural and N-ε-carboxymethyllysine also increased significantly ( p < 0.05) with roasting while furosine decreased. Roasting changed the progress of the Maillard reaction from the early stage to the advanced stage. On the other hand, there were no significant changes ( p > 0.05) in the concentration of Maillard reaction and sugar degradation products independent of the storage conditions or time and hazelnut variety, except for glyoxal, diacetyl, and 1-deoxyglucosone. Therefore, neither 5-hydroxymethylfurfural nor furosine is suggested as a storage marker of the Maillard reaction and sugar degradation.

Effects of roasting on kernel peroxide value, free fatty acid, fatty acid composition and crude protein content

Roasting nuts may alter their chemical composition leading to changes in their health benefits. However, the presence of testa may alleviate the negative effects of thermal treatments. Hence, this study aimed to explore the effects of roasting on kernel chemical quality and colour development of Canarium indicum and examine to what extent testa would protect kernels against damage from roasting. Roasting decreased peroxide value but increased free fatty acid, probably due to increased cell destruction and lack of enzyme inactivation, respectively. Protein content of kernels significantly decreased after roasting compared to raw kernels. However, testa-on kernels contained significantly higher protein content compared to testa-off kernels. Whilst colour development and mottling were observed in temperatures beyond 120°C, roasting did not alter fatty acid compositions of kernels. The mild roasting and presence of testa in kernels can be used to enhance health benefits of kernels.

Synthesis of paramagnetic dendritic silica nanomaterials with fibrous pore structure (Fe3O4@KCC-1) and their application in immobilization of lipase from Candida rugosa with enhanced catalytic activity and stability

Paramagnetic mesoporous fibrous silica (Fe₃O₄@KCC-1) was prepared and its surface was functionalized with 3-aminopropyltriethoxysilane (APTES).

Pretreatment of coconut mill effluent using celite-immobilized hydrolytic enzyme preparation from Staphylococcus pasteuri and its impact on anaerobic digestion

Biological treatment of oil and grease (O&G)-containing industrial effluents has long been a challenging issue. Practically feasible avenues to bring down their O&G load and enhance treatability are desired. In one such endeavour, the partially purified lipase from Staphylococcus pasteuri COM-4A was immobilized on celite carrier and applied for the enzymatic hydrolysis of unsterilized coconut oil mill effluent. In batch hydrolysis experiments, optimum conditions of 1% (w/v) immobilized lipase beads, one in four effluent dilution, and a contact time of 30 h resulted in 46% and 24% increase in volatile fatty acids and long-chain fatty acids and a concomitant 52% and 32% decrease in O&G and chemical oxygen demand (COD) levels, respectively. Batch anaerobic biodegradation trials with this prehydrolyzed effluent showed 89%, 91%, and 90% decrease in COD, proteins, and reducing sugars, respectively. These results were validated in a hybrid stirred tank--upflow anaerobic sludge blanket reactor. Average COD and O&G reductions effected by the hybrid reactor were found to be 89% and 88%, whereas that by the control reactor without enzymatic hydrolysis were only 60% and 47%, respectively. A maximum of 0.86 L methane gas was generated by the hybrid reactor per gram of VS added. Hence, this celite-immobilized crude lipase, sourced from a native laboratory isolate, seems to be a workable alternative to commercial enzyme preparations for the management of lipid-rich industrial effluents.

A new and general model to describe, characterize, quantify and classify the interactive effects of temperature and pH on the activity of enzymes

The common approachvs.the modern approach to analyze the effects of temperature and pH on the activity of enzymes.