Developing an optical backscatter method for determining casein micelle particle size in heated milk

Altres ajuts: Acord transformatiu CRUE-CSICA plethora of different factors, such as heat treatment, pH, soluble calcium and phosphate concentrations, colloidal calcium phosphate, ionic strength, redox potential, etc., affect functionally of critical milk components such as casein micelles, fat globules and whey proteins. These physicochemical changes induce fat- or protein-protein interactions that would be associated to changes in particle size that might be revealed using light backscatter measurements. We hypothesized that inline, simple, low-cost light backscatter measurements might have the potential to provide functionally related information, representing an interesting opportunity for process control. Casein micelle particle size and near infrared light backscatter spectra were measured in milks heat treated at 80 and 90 °C and pH 6.3, 6.7 and 7.1 in order to obtain prediction models for estimating changes in casein micelle particle size during milk heat treatment. Light intensity was measured over a spectral range of 200-1100 nm using a simple optical backscatter sensor and was implemented into models for particle size predictions as a function of heat treatment temperature and pH. Models which included an exponential factor containing a ratio of two specific wavebands were found to improve R when compared to single wavelength models. The best model exhibited an R of 0.993 and SEP of 2.36 nm. The developed prediction models show promise for in-line monitoring of whey protein denaturation and casein micelle particle size

Thermal Denaturation of Milk Whey Proteins : A Comprehensive Review on Rapid Quantification Methods Being Studied, Developed and Implemented

Heat treatment of milk signifies a certain degree of protein denaturation, which modifies the functional properties of dairy products. Traditional methods for detecting and quantifying the denaturation of whey proteins are slow, complex and require sample preparation and qualified staff. The world's current trend is to develop rapid, real-time analytical methods that do not destroy the sample and can be applied on/in-line during processing. This review presents the rapid methods that are being studied, developed and/or applied to determine and quantify the thermal denaturation of whey proteins, including spectroscopic, electrochemical and miniaturized methods. The selected methods save a significant amount of time and money compared to the traditional ones. In addition, the review emphasizes the methods being applied directly to milk and/or that have potential for on/in/at-line application. There are interesting options to quantify thermal denaturation of whey proteins such as biosensors, nanosensors and microchips, which have fast responses and could be automated. In addition, electrochemical sensors are simple to use and portable, while spectroscopy alternatives are suitable for on/in/at-line process

Prediction of riboflavin and ascorbic acid concentrations in skimmed heat-treated milk using front-face fluorescence spectroscopy

Altres ajuts: Acord transformatiu CRUE-CSICThe objective of this work was to obtain degradation kinetic models of riboflavin and ascorbic acid, and to evaluate the potential of front-face fluorescence (FFF) spectroscopy to predict their concentration in milk after thermal processing. A factorial design with three temperatures (70, 80 and 90 °C) and nine times (from 0 to 60 min) of heat treatment was used. Degradation kinetics of both vitamins were of first order. Predictive kinetic models using the Arrhenius equation had a variability coefficient of 2.26 and 3.64% for riboflavin and ascorbic acid, respectively. With fluorescent predictors such as tryptophan, Maillard compounds and riboflavin, prediction models with coefficients of variation smaller than 3.57% for riboflavin and ranging from 4.24 to 14.25% for ascorbic acid were obtained. In conclusion, FFF is a viable alternative to predict riboflavin and ascorbic acid content of milk which could allow in-line monitoring and control of thermal damage

An inline optic sensor technology to determine milk pH in yogurt manufacturing

Accurate determination of yogurt fermentation end-point (i.e., the end of the fermentation process at pH = 4.6) is essential for yogurt manufacturing. As a result of the high complexity of milk fermentation induced by lactic acid bacteria, an inadequate fermentation end-point selection could significantly compromise manufacturing cost and the final yogurt quality. Currently, acid coagulation to produce yogurt in the industry is monitored from discontinuous pH measurements that are measured manually every 10-15 minutes, a laborious and inaccurate techniquePostprint (published version

Rapid quantification of riboflavin in milk by front-face fluorescence spectroscopy : a preliminary study

The front-face fluorescence spectroscopy technique was used to establish a rapid prediction model of riboflavin concentration in milk without prior sample preparation. The prediction model developed was then compared with two conventional high performance liquid chromatography (HPLC)-based quantification methods. The method of standard addition allowed detecting a linear correlation between fluorescence intensity and riboflavin concentration in 12% (w/w) reconstituted low-heat milk powder. Validation of the model yielded an R2 of 0.99 with a standard error of prediction of 0.13 mg/L. The results suggest a potential use of front-face fluorescence spectroscopy as a simple method for off- and in-line determinations of riboflavin in milk

An in-line optical technology to control the emulsification degree in a continuous industrial emulsifier for meat sausage production

The stability of comminuted products plays an important role in the economy of meat industries. Proper formulation and the establishment of suitable emulsification conditions can significantly contribute to cooking losses control. The purpose of this research was to study the relationship between light backscatter parameters and cooking losses and develop prediction models that would allow the optimization of the emulsification process in a continuous industrial emulsifier. The optical response of meat emulsions, produced at industrial scale, depended drastically on the formulation (with and without starch) and the degree of emulsification. Furthermore, formula with starch showed significantly lower cooking losses than formula without starch, but for both formulas, several optical parameters correlated with cooking losses. Models for the prediction of cooking losses with R2 values > 0.999 were obtained with five or six statistically significant optical predictors depending on the formula. These results point out the potential of light backscatter technology as a control tool during emulsification

Effectiveness of enzymatic treatment for reducing dairy fouling at pilot-plant scale under real cleaning conditions

Altres ajuts: Acord transformatiu CRUE-CSICConventional cleaning with chemical products uses a substantial amount of water and energy to clean the fouling related to dairy production, resulting in significant economic costs. We evaluated an enzymatic treatment based on the use of protease and amylase to clean dairy fouling generated in an indirect plate heat exchanger and the spray dryer equipment of a pilot plant, representing real cleaning conditions in the dairy industry. The efficacy of the enzymatic treatment in removing fouling at 50 °C was comparable to that of the clean-in-place method, with alkaline-acid cleaning performed at a maximum temperature of 80 °C. Microbiological analysis showed that the cleaning treatments guaranteed adequate hygienic conditions of the dairy products manufactured. Monitoring fluorescence markers, such as tryptophan, riboflavin, Maillard compounds, and dityrosine could help improve the effectiveness of both alkaline and enzymatic cleaning. The enzymatic treatment fulfills dairy industry objectives, saving water and energy during washing by reducing chemical product use. Considering that enzymatic cleaning is biodegradable after use and that its economic cost is competitive compared to chemical cleaning, it represents a viable alternative to the chemical cleaning of dairy fouling

Predicción del tiempo de corte en la elaboración de queso mediante dispersión de radiación de infrarrojo próximo

La industria quesera demanda el desarrollo de instrumentos de medida en línea, sencillos, sanitarios y no destructivos, que permitan la monitorización del proceso de coagulación de la leche y la predicción de parámetros de control tales como tiempo de coagulación y, en especial, tiempo de corte. La determinación objetiva del tiempo de corte mejora el rendimiento quesero y la homogeneidad del producto. El objetivo general del presente trabajo ha sido el estudio de un sensor de fibra óptica que determina dispersión de radiación en el infrarrojo próximo, como método de monitorización de la coagulación y selección objetiva del tiempo de corte. A tal fin, se realizan tres experiencias mediante el empleo de sendos diseños de bloque completamente aleatorios, con tres réplicas cada uno. En cada una de estas experiencias se seleccionan diferentes factores y niveles experimentales para estudiar su influencia sobre la coagulación y, especialmente, sobre los algoritmos de predicción del tiempo de cort