Exogenous proteinases in dairy technology

Glavna primjena proteinaza u mljekarskoj tehnologiji je u proizvodnji sira. Prikazana je prva enzimatska te druga ne-enzimatska faza koagulacije mlijeka sirilom. Ukratko su prodiskutirane mogućnosti zamjene telećeg sirila, a u detalje razvoj imobilizirajućih sirila. Razmatrana je također mogućnost ubrzanja zrenja sira dodavanjem proteinaza. Dat je pregled sporedne upotrebe proteinaza uključujući proizvodnju proteinskih hidrolizata, modifikaciju proteina i proizvodnju dječje hrane.The principal applications of proteinases in dairy technology are in cheese manufacture. The enzymatic primary phase and non-enzymatic secondary phase of rennet coagulation of milk are reviewed. Aspects of veal rennet substitutes are briefly discussed and developments in immobilized rennets considered in detail. The possibility of accelerating cheese ripening via added proteinases is also considered. Minor applications of proteinases including production of protein hidrolyzates, protein modification and baby food manufacture are reviewed

Advanced Taste Sensors Based on Artificial Lipids with Global Selectivity to Basic Taste Qualities and High Correlation to Sensory Scores

Effective R&D and strict quality control of a broad range of foods, beverages, and pharmaceutical products require objective taste evaluation. Advanced taste sensors using artificial-lipid membranes have been developed based on concepts of global selectivity and high correlation with human sensory score. These sensors respond similarly to similar basic tastes, which they quantify with high correlations to sensory score. Using these unique properties, these sensors can quantify the basic tastes of saltiness, sourness, bitterness, umami, astringency and richness without multivariate analysis or artificial neural networks. This review describes all aspects of these taste sensors based on artificial lipid, ranging from the response principle and optimal design methods to applications in the food, beverage, and pharmaceutical markets

Non-enzymatic electrochemical sensing of glucose with nano-structured and functionalised diamond electrodes

Electrochemical sensing is a powerful tool for the rapid detection of (bio)molecules in fluids, and is frequently used in clinical analysis and diagnostics. Diamond is arguably the best electrode material for its robustness, wide potential window, very low background current, biocompatibility and self-cleaning features. Nowadays, there is a new trend leading to electrodes getting smaller. One of the current challenges in the development of diamond micro-electrodes is to increase the sensitivity of the diamond electrode, while the electrode’s dimensions decrease. An interesting biomolecule to detect is glucose. 2.8% of the world population suffers from diabetes, these people need to measure their blood sugar level and manage this level by dispensing insulin in their body when needed. A glucose sensor is used to determine the amount of glucose in the blood. Boron-doped diamond (BDD) is an interesting material for the non-enzymatic detection of glucose.In this thesis project, study has been done to the nanostructuring and functionalisation effects on the performance of sensing glucose by using diamond electrodes. Measurements have been done with different types of electrodes: bare BDD, acid cleaned BDD, BDD functionalised with gold nanoparticles, BDD with a nanowire surface structure, and BDD with a nanowire surface structure and gold nanoparticles on top. It was found possible to detect glucose with three of these samples: bare BDD, BDD with gold nanoparticles, and the nanostructured BDD functionalised with the gold nanoparticles. The other two electrode types did not give any reduction/oxidation peaks, which is attributed to the oxygenated surface resulting from their fabrication processes. The three glucose-detecting electrodes showed linear behaviour in a range of 1-10 $mM$, which is in line with the detection range of glucose in human blood. The sensitivities achieved with bare BDD, BDD with gold nanoparticles, and the nanostructured BDD functionalised with the gold nanoparticles are 0.022, 0.429, and 0.136 mA/mMcm^{2}, respectively. The addition of gold particles improves the sensitivity for glucose substantially and works like an electrocatalyst. Making use of electrocatalysts is an interesting and useful functionalisation for direct non-enzymatic glucose sensing, because sensing glucose with bare BDD is a kinetically very slow process. Results of such high sensitivities for BDD with gold nanoparticles were not published in literature yet, so this is a promising achievement that asks for continuation of research in this field.Mechanical Engineering | Micro and Nano Engineerin