Turkey breast roasting – Process optimization

The objective of the present study was to perform experimental and theoretical analyses of the process of roasting turkey breast slices in a steam-convection oven with a view to determining the optimal values of temperature and steam saturation during roasting, under the assumption of a constant slice thickness. The roasting process was conducted at air temperature of 160 °C, 180 °C, 200 °C and 220 °C and steam saturation of 0%, 20%, 50%, 70% and 90%. Two qualitative criteria based on eating quality and nutritive value have been applied in process optimization. Those criteria proved to be mutually opposing. As regards eating quality, the best product was that roasted at a temperature of 160 °C without the application of steam in the oven. The same product was characterized by the lowest nutritive value. Nevertheless, it should be noted that the protein content of turkey meat, largely responsible for its nutritive value, is related to changes in protein concentrations in samples resulting from weight loss during cooking. The highest nutritive value was noted in respect of the product roasted at a temperature of 200 °C with 20% steam saturation. Both optimal products were microbiologically safe.     

Determination of optimum processing conditions for hot‐air roasting of hulled sesame seeds using response surface methodology

Sesame paste (tahin) is produced by milling hulled, roasted, sesame seeds. In this study, a hot‐air roasting process for the production of sesame paste was optimised by response surface methodology (RSM) over a range of air temperatures (120–180 °C) for various times (30–60 min). The colour parameters (L, a and b values), browning index (BI), hardness, fracturability and moisture content of the seeds were used as response parameters to develop predictive models and optimise the roasting process. Increases in roasting temperature and time caused increases in the a and b values and in the BI. The hardness and fracturability of seeds also decreased with increasing roasting temperature and time. The quadratic and linear models developed by RSM adequately described the changes in the colour values and textural parameters, respectively. The result of RSM analysis showed that all colour parameters and textural parameters should be used to monitor the roasting of sesame seeds in a hot‐air roaster. To obtain the desired colour and texture, the optimum roasting range for production of sesame paste was determined as 155–170 °C for 40–60 min. Copyright © 2006 Society of Chemical Industry     

A numerical approach for the analysis of the coffee roasting process

A numerical model of the coffee roasting process under operating conditions is proposed. This numerical tool is able to simulate the behaviour of all the components of a batch roaster as well as the roasting process of the coffee beans within the drum. The model evaluates the heat and mass transfer between a hot air flow and the coffee beans during the roasting process on the basis of the physical properties of the coffee and the operation of the roasting machine. Different submodels are included in the modelling in order to address particular thermo-physical processes, such as the evaporation of coffee moisture and the heat released or absorbed by the beans due to the roasting reactions.     

A reactor engineering approach to describe bacterial inactivation during continuous UV-C light processing

A reactor engineering approach was used to mathematically describe microbial inactivation during continuous UV-C light processing of liquid foods. The method was followed to analyze the survival curves of Lactobacillus rhamnosus inoculated into sucrose model solutions prepared at different concentrations (8, 10 and 12 g sucrose per 100 g of solution) and pH values (pH 3, 4.5 and 6), and further processed at two different residence times (4.85 and 29.9 min). The inactivation process was considered as an irreversible elemental reaction of unknown order occurring in a continuous stirred tank reactor. The proposed model was expressed in terms of the logarithmic reduction in microbial population and its straight-line form allowed the easy estimation of the inactivation rate constant and reaction order. Results indicated that inactivation of L. rhamnosus followed a variable order kinetic, moving from a first-order rate during unsteady-state operation to a near zero-order inactivation when steady-state operation was reached. Steady-state was reached faster (0.48 ± 0.11 min⁻¹ vs. 0.37 ± 0.7 min⁻¹, p < 0.05) and with a higher steady-state log reduction (5.9 ± 0.2 vs. 5.4 ± 0.6 log CFU/mL, p < 0.05) in experiments conducted with the lowest residence time, UV-C dose and power density (4.85 min, 12.8 J/cm² and 6.6 J/cm³).     

An indirect approach for egg weight sorting using image processing

An indirect approach for egg weight sorting, using image processing, is proposed in the paper. The eggs are sorted in four classes by weight. Regression analysis is used for approximation of relationship between egg weight and egg geometric parameters—perimeter, area, major and minor axis, shape index and shape factor. The values of the geometric parameters, collected by image processing and the one, collected by traditional method, are compared for each egg sample, using percent differences between data. The experimental results show that the most significant parameter for egg weight indirect measurement is the egg area, with correlation coefficient 0.989. The mathematical model for the relationship between weight and area of the egg is defined with coefficient of determination 0.978. The classification accuracy is achieved within the eggs test sample sorting. The total classification error is 2.5% for test set and 12.5% for training set.     

A time–temperature rheological approach for examining food polymer gelation

The viscoelastic behavior of food polymers during gelation covers a wide oscillatory frequency spectrum, however, commercial rheometers are restricted to a limited range. Application of the time–temperature superposition (TTS) principle and the modified Cole–Cole (MCC) analysis resolves this problem by laterally shifting isothermal frequency data so they superpose to form a single master curve. This paper gives a systematic approach for applying both TTS and MCC analysis for studying the behavior of food polymers during gelation, using de-acyl gellan in the presence of co-solutes (sucrose and corn syrup) as an example.     

Human digestion – a processing perspective

The human digestive system is reviewed in the context of a process with four major unit operations: oral processing to reduce particle size and produce a bolus; gastric processing to initiate chemical and enzymatic breakdown; small intestinal processing to break down macromolecules and absorb nutrients; and fermentation and water removal in the colon. Topics are highlighted about which we need to know more, including effects of aging and dentition on particle size in the bolus, effects of different patterns of food and beverage intake on nutrition, changes in saliva production and composition, mechanical effects of gastric processing, distribution of pH in the stomach, physicochemical and enzymatic effects on nutrient availability and uptake in the small intestine, and the composition, effects of and changes in the microbiota of the colon. Current topics of interest including food synergy, gut–brain interactions, nutritional phenotype and digestion in the elderly are considered. Finally, opportunities for food design based on an understanding of digestive processing are discussed. © 2015 Society of Chemical Industry     

Importance of weather monitoring for agricultural decision‐making – an exploratory behavioral study for Oklahoma Mesonet

BACKGROUND

The Oklahoma Mesonet (the statewide environmental and weather monitoring network) has monitored changes in weather patterns since 1994 to provide accurate and timely mesoscale weather information to farmers and other groups. Studies are still scarce that would quantitatively assess farmers' perceptions about the value of the Oklahoma Mesonet contributions to agricultural operations, profitability of land management, and decision making. This paper aims to analyze those questions by means of an exploratory empirical study in Oklahoma for two groups of Mesonet users and non‐users.

RESULTS

Familiarity with and application of Mesonet information determines farmers' profitability assessments and decision making. Farmers' perceptions are also influenced by the degree of previous exposure to weather‐related losses. The median estimate of the economic value of Mesonet information is $1000 per year. Mesonet users perceive higher profitability from the application of Mesonet data at 7.6/10, whereas Mesonet non‐users provided an average assessment of 2.6/10.

CONCLUSIONS

Consistent use of Mesonet information results in a higher assessment of the importance of Mesonet. This research provides some initial insights into farmers' perceptions about the value of Oklahoma Mesonet information, which could guide stakeholders in developing measures to better serve farmers with environmental monitoring data for improved farm decisions. © 2018 Society of Chemical Industry     

Development of extruded snacks using soy,sorghum, millet and rice blend – A response surface methodology approach

Response surface methodology (RSM) based on a five‐level‐three‐factor central composite rotatable design (CCRD) was employed for optimisation of formulation for production of a soy‐fortified millet‐based extruded snack. Effects of amount of ingredients such as ragi (40–50%), sorghum (10–20%) and soy (5–15%) on the physical properties like bulk density, expansion ratio, water absorption index and water solubility index of snacks were investigated. Significant regression models that explained the effects of different percentages of ragi, sorghum and soy on all response variables were determined. The coefficients of determination, R², of all the response variables were higher than 0.90. Based on the given criteria for optimisation, the basic formulation for production of millet‐based extruded snack with desired sensory quality was obtained by incorporating with 42.03% ragi, 14.95% sorghum, 12.97% soy and 30% rice.     

Fruit pectins – A suitable tool for screening gelling properties using infrared spectroscopy

Found in higher plants, pectins are natural hydrocolloids whose extraction is controversial as it is condition-dependent. To optimize the methodology for extracting and isolating pectins and verifying the effect on their structural characterization, a factorial 2³ assay was planned, using the following independent variables: pH, duration of heating and nature of alcohol in fruits with different kinds of morphologies. The fruits were grouped into those that produce good jams and jellies (group I), those that have a variable chemical composition and contain fiber (group II), and those that contain starch (group III). The results were compared using variance analysis and Duncan test. The degree of methoxylation (DM) of the pectin isolated from the mesocarp of citrus and guava fruits (whole) was associated linearly with all independent variables. However, the pectin yield was influenced only by pH and duration of heating. The interaction between the nature of alcohol and the duration of heating were shown to be significant, a longer heating time and ethanol being better for the two kinds of fruit. In group I, the pectins isolated showed best DM associated with high yield, whilst group II yield was below the limit for producing jams and jellies, despite high DM. Group I fruits displayed characteristics that favor gel formation, whilst group II and group III proved to be deficient in at least one of the dependent variables. This study has validated as analytical tool for isolating and characterizing the structure of pectins, mainly those naturally occurring in tropical fruits.     

Optimization of roasting conditions as an useful approach for increasing antioxidant activity of carob powder

Antioxidant activity, gastrointestinal solubility of polyphenols and formation of different classes of Maillard reaction products (MRPs) that occurs during thermal processing of carob powder was investigated in relation to different roasting time-roasting temperature combinations applied. Principal component analysis (PCA) was used to group carob powders with the aim of proposing optimal roasting conditions for obtaining the one with the highest biological activity that can be expected after undergoing the simulation of gastrointestinal digestion. Results showed that antioxidant activity of carob powder can be significantly increased by roasting due to improved polyphenol solubility and formation of the early-stage MRPs. Fluorescent MRPs, HMF and furfural, known for their toxic properties, were the most abundant in samples roasted under more severe time/temperature conditions. Carob powder roasted at 130 °C for 30 min yielded the highest antioxidant activity and the lowest toxic MRP formation.     

An alternative encapsulation approach for production of active chitosan–propolis beads

Encapsulation is a promising technology to carry natural active substances, preventing their loss and maintaining their stability until use. Beads of chitosan‐containing propolis have been prepared using a mono‐pore filter device, which permits the encapsulation of natural polyphenols avoiding heat treatments, high shear rates and the use of toxic solvents. Beads proved to be active against Bacillis cereus, Escherichia coli, Listeria innocua, Pseudomonas fluorescens, Yarrovia lipolytica and three moulds strains; the highest effect was found against Staphylococcus aureus (MIC 0.8 mg beads mL^?1). Results in liquid cultures of S. aureus evidenced that beads were able to release the flavonoids from propolis: the diffusion of the active compounds is a key factor in the exploitation of the microbial activity. The obtained chitosan–propolis beads represent an example of natural antimicrobial delivery system that could be used to prevent the growth of pathogenic/spoilage bacteria in food applications.     

Numerical simulation of solid–liquid food mixture in a high pressure processing unit using computational fluid dynamics

Temperature distribution, velocity and pressure profiles during high pressure compression (500 MPa) of liquid food (water) and solid–liquid food mixture (beef fat and water), within a three dimensional cylinder basket is simulated. The computations domain in both cases was performed for a cylinder with a diameter of 38 mm and height of 290 mm, which are the same dimensions of the high pressure unit “FOOD-LAB model S-FL-850-9-W” available at the University of Auckland, New Zealand. The governing equations for continuity, momentum and energy conservation are solved using a commercial computational fluid dynamics (CFD) package (PHOENICS), version 3.5, which is based on a finite volume method of solution. The simulation for liquid food only shows the effect of forced and free convection flow on the temperature distribution in the liquid at the early stages of compression. This is due to the difference between the velocity of the pumping fluid as it enters the cylinder inlet hole (10⁻²–10⁻³) m s⁻¹ and the velocity in the treatment chamber (10⁻⁸–10⁻⁹) m s⁻¹. The simulation for the solid–liquid mixture shows as well, the temperature distribution in the solid and liquid at different stages of compression. It shows that the solid pieces are more heated than the liquid, which is due to the difference in their compression heating coefficient. Validation of the computed temperature in both cases is found to be in an agreement with those measured experimentally and reported in the literature.     

连续小波变换-纯变量法解析气相色谱-质谱重叠信号

提出了连续小波变换-纯变量法(CWT-PVA)解析气相色谱-质谱(GC-MS)重叠信号的新方法.在CWT-PVA中,利用CWT对重叠色谱峰处理,得到重叠组分数目,再利用PVA解析重叠质谱数据,得到纯组分质谱信息,并进而计算出各组分色谱信息,在质谱和色谱两方面完成GC-MS重叠信号定性定量解析.结果表明,CWT-PVA是一种简便有效的GC-MS重叠信号解析方法.     

A new approach using consumers' ‘drinking histories’ to explain current wine acceptance

Through habit formation and the acquisition/reinforcement of liking for alcoholic beverages over time, consumption and exposure may shape wine sensory preferences. Aiming to evaluate whether consumers' current red and white wine sensory hedonic likings may be explained by their previous (and/or ongoing) alcoholic beverage consumption and behaviour (‘drinking history’), participants from a ‘drinking history’ study (divided into 2 age groups: 30-40 y and 50-60 y) evaluated 9 red (N = 135) and 9 white (N = 148) wines covering two sensory dimensions: sweet-not-sweet and light-heavy. Multiple regression analysis included consumption and behavioural variables from different periods of participants' ‘drinking histories’ as independent variables and showed that the sweet-not-sweet dimension is more likely to be influenced by ‘drinking histories’. Current wine acceptance depends on consumption patterns (previous drinking history’ phase for white wine and ongoing phase for red wine) and recent behaviour, particularly for the older group. Consumers' preference moves first over the sensory dimension from sweet to not-sweet and later along the sensory dimension light-heavy.     

A thermodynamic approach to heat and mass transport in stored agricultural products

The fundamental laws of equilibrium thermodynamics and a mass transport equation based on non-equilibrium thermodynamics are used to analyze the temperature and moisture concentration fields in the porous medium of an agricultural storage bin. The non-linear differential equations are integrated numerically and the results are shown to compare favorably with experimental data obtained from the literature.     

Microwave decontamination processing of tahini and process design considerations using a computational approach

Tahini, as a low moisture food product, is linked to several outbreaks of Salmonella recently even though a high temperature roasting (of sesame seeds) through its production is involved. Therefore, a final decontamination approach might be required for safety. Considering its higher oil content and lower thermophysical properties, conventional approaches are not easy to apply while preserving the quality attributes. Therefore, microwave heating was used for decontamination purpose. For this purpose, a computational mathematical model was developed first to determine the temperature distribution of tahini during microwave heating, and microbial inactivation studies for Salmonella enteritidis (ATCC 13076) were carried out. Changes in color and peroxide values were evaluated, and the experimentally validated model was further used to design an industrial process to achieve a 5-log cycle reduction as an efficient decontamination processing. The target temperature over 80 °C within the sample was demonstrated to achieve such a process, and industrial scale process conditions were presented for 262 kg/h process capacity.