Search

The United States Food and Drug Administration (U.S. FDA) has identified improper ("slow") cooling as an important contributing factor in foodborne illness outbreaks. The efficacy of post-thermal treatment cooling techniques on controlling surrogate Escherichia coli growth in taco meat, chili con carne with beans, and low-sodium marinara sauce was evaluated. Each product was cooked to 73.9°C, portioned to 2- and 3-inch depths in stainless steel steam table pans, and cooled to 60°C ± 5°C before inoculation with E. coli. Pans were prepared with different cover methods to allow or restrict air exposure and then placed inside a -20°C commercial walk-in freezer or situated in ice water baths inside a 4°C commercial walk-in refrigerator. Product temperatures were recorded for 24 hours. Microbial populations were enumerated at 0, 4, 8, 12, and 24 hours. Temperature data for taco meat and chili con carne with beans revealed that few cooling methods met the 2017 FDA Food Code cooling criteria, while data for low-sodium marinara sauce showed that no cooling method met the Food Code chilling criteria. Population changes were < 0.50 log10 CFU/g over 24 hours in all products, indicating that all cooling methods were low risk for microbial proliferation and were therefore effective at controlling E. coli within these products. [ABSTRACT FROM AUTHOR]

A model was developed to predict the growth of Bacillus cereus from spores during cooling of cooked pasta. Cooked pasta was inoculated with a cocktail of four strains of heat‐shocked (80 °C/10 min) B. cereus spores to obtain a final spore concentration of approximately 2 log CFU/g. Thereafter, growth was determined at isothermal temperatures starting at 10 °C and every three degrees up to 49 °C. Samples were removed periodically and plated on mannitol egg yolk polymyxin agar. The plates were incubated for 24 hr at 30 °C. Baranyi, Huang, and modified Gompertz primary growth models were used to fit growth data. The modified Ratkowsky secondary model was used to fit growth rates determined by the primary growth models with respect to temperature. All three primary models fitted the growth data well. The modified Ratkowsky secondary model adequately fit growth rates generated by the three primary models (R2 values ranging from 0.96 to 0.98). After acceptable prediction zone (APZ) validation and goodness of fit statistical analyses, it was determined that the Baranyi primary growth model was best suited for these data. For both single‐rate exponential cooling and biphasic linear cooling model validation, all Baranyi model predictions (n = 24 and 28, respectively) fell within the APZ (−1.0 to 0.5 log CFU/g). The model will assist institutional food service settings to determine the safety of cooked pasta subjected to longer cooling times or stored at improper temperatures. Practical Application: Predictive model can be used to estimate extent of microbial growth during cooling of cooked pasta and in designing HACCP program and setting of critical control levels. Retail food industry would need fewer challenge studies to validate the safety of their products. The model will provide regulatory agencies and food industry with an objective means of assessing the microbial risk and ensuring that the public is not at risk of acquiring food poisoning. [ABSTRACT FROM AUTHOR]

Abstract Background Vacuum cooling (VC) is a cooling technology for moist and porous foodstuffs with superiority in cooling rate, uniformity and hygiene, and low energy consumption. However, there are still some disadvantages that weaken the competitiveness of industrial applications such as the inevitable mass loss and uneven cooling in different parts of leafy vegetables. In order to improve the performance of VC, many efforts have been performed. Scope and approach In this review, the basic information of VC and the main applications for fruit, vegetables and meat products as well as limitations are described first. Improvements for enhancing performances of this technology in terms of operation processes including pre-treatment, technical optimization and integration, as well as equipment upgrade, and optimized operation conditions such as final pressure and pressure reduction rate are discussed. In addition, the limitation and further prospects of VC in the food industry are also mentioned. Key findings and conclusions The findings presented in this review demonstrated that optimizing operation processes and controlling operation conditions can effectively improve the performance of VC including mass loss, cooling rate and energy consumption and temperature distribution. However, many enhancing strategies still have limitation for applied in the food industry. Future trends of VC are the study of moisture migration characteristics based on food microstructure and multi-functional optimization of VC process or system. It is hoped that the current review can provide some guidance for further developments of the VC technology. Highlights • Contemporary applications of vacuum cooling to foods are presented. • Limitations in application and performance of vacuum cooling are discussed. • Innovative operation processes to improve vacuum cooling technology are assessed. • Strategies to refine operation conditions of vacuum cooling are outlined. • Key research trends comprise moisture migration and multi-functional optimization. [ABSTRACT FROM AUTHOR]

This study presents a novel methodology to model the cooling processes of horticultural produce using realistic product shapes rather than commonly used simplified 3D shapes, such as spheres. Variable 3D apple and pear models were created by means of a validated geometric model generator based on X-ray computed tomography images. The fruit were randomly stacked into a geometrical model of a corrugated fibreboard box using the Discrete Element Method. A forced-air cooling process was simulated for three such apple filling patterns using CFD and the results were compared to those obtained with fruit represented by equivalent spheres. No significant difference in average aerodynamic resistance between the real apple shape and its spherical representation was found. The main contributor to the overall pressure drop was the package design rather than product shape. However, large differences in local air velocity and convective heat transfer coefficients were found between the two representations. The degree of cooling uniformity between individual fruit was overestimated when using simplified product shapes: real apple fruit shapes cooled less uniform. This difference between real and simplified product shapes was even larger for a box filled with pear fruit that are more different from a spherical shape. These results demonstrate that improved computer-aided design approaches help in simulating more accurate convective cooling processes. In a next step, such simulations will be used for multi-objective optimization of packaging in terms of cold chain efficiency and cooling uniformity. [ABSTRACT FROM AUTHOR]

Forced-air cooling (FAC) is a widely applied postharvest technology to rapidly remove the field heat of packed fresh fruit. The cooling uniformity of the fruit in different pallets and cartons during FAC is critical but often remains unknown in commercial operations. This study investigated the cooling rate and heterogeneity of packed citrus fruit in a full-scale, forced-air precooler with 40 pallets of fruit. The influence of package design (package type and wrapping) and fruit size on the precooling performance was quantified in several experiments with three types of citrus fruits (‘Navel’ orange fruit, ‘Nova’ mandarin fruit and ‘Eureka’ lemon fruit). Results showed that the cooling heterogeneity mainly occurred along the flow direction. Cooling was uniform between horizontal regions at the same side of the pallets and between the different heights in the precooler. High resolution measurements with 25–30 sensors in a single pallet gave an even better insight in this heterogeneity. Fruit wrapping induced a much slower cooling rate and larger cooling heterogeneity, especially in the cartons at the outflow side of the pallet. The ‘Nova’ mandarin fruit in Opentop cartons cooled 24% (at the inflow side of the pallet) and 42% (at the outflow side of the pallet) faster than the ‘Eureka’ lemon fruit with similar fruit size in Supervent cartons, showing the impact of packaging design. These experiments quantified the cooling heterogeneity of the commercial precoolers. [ABSTRACT FROM AUTHOR]

Temperature controlled food transport is essential for human safety and to minimise food waste. The thermal properties of food are important for determining the heat transfer during the transient stages of transportation (door opening during loading and unloading processes). For example, the temperature of most dairy products must be confined to a very narrow range (3-7 °C). If a predefined critical temperature is exceeded, the food is defined as spoiled and unfit for human consumption. An improved empirical model for the thermal conductivity and specific heat capacity of a wide range of food products was derived based on the food composition (moisture, fat, protein, carbohydrate and ash). The models that developed using linear regression analysis were compared with the published measured parameters in addition to previously published theoretical and empirical models. It was found that the maximum variation in the predicated thermal properties leads to less than 0.3 °C temperature change. The correlation coefficient for these models was 0.96. The t-Stat test (P-value >0.99) demonstrated that the model results are an improvement on previous works. The transient heat transfer based on the food composition and the temperature boundary conditions was found for a Camembert cheese (short cylindrical shape) using a multiple dimension finite difference method code. The result was verified using the heat transfer today (HTT) educational software which is based on finite volume method. The core temperature rises from the initial temperature (2.7 °C) to the maximum safe temperature in ambient air (20.24 °C) was predicted to within about 35.4 ± 0.5 min. The simulation results agree very well (+0.2 °C) with the measured temperature data. This improved model impacts on temperature estimation during loading and unloading the trucks and provides a clear direction for temperature control in all refrigerated transport applications. [ABSTRACT FROM AUTHOR]

Abstract: Cooling is applied to horticultural products to reduce exposition time to inappropriate temperatures. In the present work, a mathematical model was proposed to describe the cooling behavior of lime fruit and to determine the thermal convection coefficient (h) involved. The Galerkin finite element method was used to obtain a numerical solution of the model and results were evaluated by comparing with experimental information. The coefficient h was dependent on fruit position in the cooling system, varied between 3.7 and 100.6 W/m2  °C with air velocity, and results corresponding to forced air were expressed in terms of Nusselt and Reynolds numbers. Practical Applications: A methodology was developed to determine the thermal convection coefficient (h) in the cooling process of a horticultural product. The procedure was based on fundamental heat transfer laws that were analyzed through the finite element method; however, it was step by step described and was programmed in the Matlab environment, which allows an easy application to other process conditions. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the ability of Bacillus cereus spores to germinate and grow in order to determine a safe cooling rate for cooked rice, beans, and pasta, rice-chicken (4:1), rice-chicken-vegetables (3:1:1), rice-beef (4:1), and rice-beef- vegetables (3:1:1). Samples were inoculated with a cocktail of four strains of heat-shocked (80°C for 10 min) B. cereus spores (NCTC 11143, 935A/74, Brad 1, and Mac 1) to obtain a final spore concentration of approximately 2 log CFU/g. Thereafter, samples were exponentially cooled through the temperature range of 54.5 to 7.2°C in 6, 9, 12, 15, 18, and 21 h. At the end of the cooling period, samples were removed and plated on mannitol egg yolk polymyxin agar. The plates were incubated at 30°C for 24 h. The net B. cereus growth from spores in beans was <1 log after 9 h of cooling, but the pathogen grew faster in rice and pasta. In combination products, the net growth was as follows: 3.05, 3.89, and 4.91 log CFU/g in rice-chicken; 3.49, 4.28, and 4.96 log CFU/g in rice-beef; 3.50, 4.20, and 5.32 CFU/g in rice--chicken--mixed vegetables; and 3.68, 4.44, and 5.25 CFU/g in rice--beef--mixed vegetables after 15, 18, and 21 h of cooling, respectively. This study suggests safe cooling rates for cooling cooked rice, beans, pasta, rice-chicken, rice-chicken-vegetables, rice-beef, and rice-beef-vegetables to guard against the hazards associated with B. cereus. [ABSTRACT FROM AUTHOR]

Food freezing is one of the most energy-intensive technologies used to preserve food products in domestic manufacturing operations. To acquire the heat load profile during freezing process, measurements and simulation have been conducted on a running refrigerated warehouse as part of a large cold storage. Continuous temperature measurements have been taken in the chosen room and rooms around it, as well as the outdoor temperature and the evaporation temperature in air coolers. The dynamic heat gain from warehouse structures and air coolers was simulated based on the measured temperatures and operation mode of refrigeration system. An verified food freezing model was applied to model the heat load of food products to analyze the influence of air temperature on freezing process. Results show that the heat load through warehouse structures has little impact on room temperature compared to the heat load of air coolers and food products. Due to the large transients induced by on/off control strategy of refrigeration system, the refrigeration capacity changes greatly during freezing process which has the same trend as the heat load of food products. It can be concluded the heat load of refrigerated warehouse varies greatly at different stages of freezing process. Different control strategies of refrigeration system need to be applied at different stages of food freeing from energy-saving point. [ABSTRACT FROM AUTHOR]

In recent years, the temperature of processed olives in many olive-growing areas was often close to 30 °C, due to the global warming and an early harvesting period. Consequently, the new trends in the extraction process have to include the opportunity to cool the olives or olive paste before processing to obtain high quality EVOO. A tubular thermal exchanger was used for a rapid cooling treatment (CT) of olive paste after crushing. The results did not show a significant difference in the oil yield or any modifications in the legal parameters. The cooling process determined a significant improvement of phenolic compounds in all the three Italian cultivar EVOOs analyzed, whereas the volatile compounds showed a variability largely affected by the genetic origin of the olives with C 6 aldehydes that seem to be more stable than C 6 alcohols and esters. [ABSTRACT FROM AUTHOR]

In this study we investigated the combined effect of shearing and cooling rate in the rheology of organogels developed in high oleic safflower oil by ( R )-12-hydroxystearic acid (HSA), its primary amide derivative [( R )-12-hydroxyoctadecanamide, HOA], and the N -octadecyl derivative of HOA [( R )- N -octadecyl-12-hydroxyoctadecanamide, OHOA]. The experimental set up to develop the organogels involved: 1). The use of quiescent (0 s − 1 ) or shearing (300, 600, and 1200 s − 1 ) conditions during cooling the gelator solutions (2%) just until achieving the gelator's melting temperature (T M ) in the vegetable oil, to then continuing the cooling under static conditions until achieving 15 °C) The use of cooling rate protocols involving a constant cooling rate of 1 °C/min (CR 1 ) or 10 °C/min (CR 10 ) in the shearing and static stages, or variable cooling rates in each stage (i.e., VR 1–10 or VR 10–1 ). The elasticity of the organogels ( G ′) was measured while cooling under static conditions, once the systems achieved 15 °C, and after 60 min at this temperature. The rheological results obtained at 15 °C showed a cooling rate and molecular weight-dependent effect of shearing on G ′. We propose that the molecular relaxation time of gelator molecules, and its increase as molecular weight increases and as temperature decreases, plays an important role on the gelator's susceptibility to go through a shear induced crystallization process. Therefore, high molecular weight molecules like OHOA (551.97 Da) would remain stretched by shearing longer times than HSA (300.49 Da) and HOA (299.49 Da). Thus, when shearing was applied while cooling at the higher cooling rate (i.e., CR 10 and VR 10–1 ), the stretched OHOA molecules would lead to the development of mesophase precursors that upon further cooling under quiescent conditions, crystallize developing a well-structured organogel. In contrast, stretched low molecular weight molecules (i.e., HSA and HOA) with shorter relaxation time would dissolve back to the isotropic state during cooling. Additionally, the rheological results of HSA and HOA organogels suggested that the shear induced crystallization process might be dependent on the gelator polarity also. These results show that the application of shear and the extent of its application as temperature decreases until achieving T M , have important implication on the self-assembly of gelator molecules, and therefore in the organization and rheology of the three-dimensional crystal network of the organogel. [ABSTRACT FROM AUTHOR]

The aim of this study was to gain a better understanding of the tenderisation mechanism associated with very fast chilling (VFC) of beef muscle. Hot-boned striploins from 36 carcasses were allocated to a treatment (control, delayed or immediate chilling below 0 °C), and each striploin was divided into three equal portions and allocated to a time post-mortem (2, 5 or 14 d). Immediate chilling resulted in lower peak force values at 2 d post-mortem and lower particle size after 5 d post-mortem. Both chilling treatments significantly improved the WHC by reducing drip loss and cooking loss. Sarcomere lengths were not affected by chilling treatments, although fragmentation and cleavage of muscle fibres were evident along the fibre length, possibly contributing to the reduction in peak force values at 2 d post-mortem. Both delayed and immediate chilling resulted in a higher pH at 4 and 24 h post-mortem, and colour parameters were modified. These results suggest that VFC has potential for accelerating tenderisation early post-mortem by a combination of biochemical and biophysical effects. [ABSTRACT FROM AUTHOR]

Forced air cooling studies are hindered by the practical difficulties and cost associated with pallet scale investigations. Produce simulators are a potential solution for overcoming some of these difficulties. Despite their common use in precooling research, there are a lack of design guidelines for such simulators in the literature which in some case has led to their inappropriate use. This review examines previous use of produce simulators in produce cooling studies in the context of transport phenomena theory. This allows constraints to be proposed which facilitate the design of produce simulators that can replicate transport phenomena in horticultural produce. These include the requirements of geometric and thermal property matching as well as the practical constraints imposed on produce simulators. It is suggested that future computational modelling work is well suited to the establishment of produce simulator design guidelines which incorporate complex effects such as the impact of variation in produce geometry on flow. The material engineering challenges posed by produce simulators are also discussed. [ABSTRACT FROM AUTHOR]

Starch was isolated from tamarind kernels, which are at present considered as waste. It was compared with corn and mung bean starch for its physicochemical, rheological, and morphological properties. Tamarind kernel starch showed significantly lower amylose content, light transmittance, solubility, and higher swelling power in comparison to corn and mung bean starch. The micrographs of tamarind kernel starch revealed its small oval shape granules with smooth surfaces. X-ray diffraction pattern of tamarind kernel starch was similar to corn starch with strong diffraction peaks at 15, 17, and 23° (2θ). Changes in storage modulus (Gʹ), loss modulus (Gʹʹ), and loss tangent (tan δ) during heating of starches showed the lowest peak Gʹ for tamarind kernel starch, whereas the highest was observed for corn starch. Changes in Gʹ and Gʹʹ during cooling, holding and subsequently heating were also studied. The frequency dependence of Gʹ and Gʹʹ of starches measured at 25 and 95°C revealed their weak gel behavior. During cooling tamarind kernel starch showed lower increase in Gʹ in comparison to other starches. Tamarind kernel starch was different from corn and mung bean starch in exhibiting highest peak, breakdown, and lowest setback viscosity. Tamarind seeds have potential as a relatively new, cheap, and underutilized source of starch in food applications. [ABSTRACT FROM PUBLISHER]

Desiccant wheel based air handling units are of great interest in drying processes, such as in the pharmaceutical and food industries, due to the significant energy savings that can be achieved compared to conventional systems. Units based on desiccant wheels are usually optimized in peak conditions, while little attention is given to operation at part load and off design conditions. The aim of this work is to analyze the effects of different control strategies of desiccant wheels on regeneration heat consumption. The analysis is performed through a phenomenological desiccant wheel model, which is validated with experimental data collected in typical working conditions of the drying room investigated in this work. Five control strategies are proposed, highlighting that each one leads to significantly different heat consumption. Finally, an additional simplified control is introduced, showing that it can effectively reduce thermal power consumption compared to conventional control strategies. [ABSTRACT FROM AUTHOR]

A study was undertaken to standardise processing treatments for optimising resistant starch (RS) formation in rice starch. The effect of processing conditions on the RS content of rice starch was studied in 48 treatments by autoclaving at 121°C and 141°C for 20, 40 and 60 minutes without moisture and with 10, 20 and 40 percentage moisture levels. After autoclaving, the samples were cooled at room temperature and at -20°C. The yield of RS was found to be maximum in samples autoclaved at 141°C for 40 minutes with 10 per cent moisture and cooled at -20°C. Increasing the duration of autoclaving up to 60 minutes at a lower temperature of 121°C was also found to be effective in improving the RS content of rice starch. RS formation not only depends on a single factor but also on multiple factors like time and temperature of autoclaving, moisture as well as cooling conditions. [ABSTRACT FROM AUTHOR]

Regulation of sugar metabolism in potato tubers stored at low temperatures has significant ramifications for producers and consumers of potato chips and French fries. Low-temperature storage reduces losses due to sprouting and disease but induces undesirable accumulation of the reducing sugars glucose and fructose. These sugars react with free amino acids during frying to produce dark-colored and bitter-tasting products that have elevated levels of acrylamide, a suspected human carcinogen. Elevated amounts of tuber glucose and fructose are produced when vacuolar acid invertase (VInv) hydrolyses sucrose derived from starch degradation. In this study, wild-type tubers and tubers in which VInv expression was reduced by RNA interference were used to study the temperature-dependent regulation of sugar accumulation and expression of carbohydrate metabolism genes during and after the cooling of tubers to 9 or 3 °C. It was found that transcriptional control of genes central to carbohydrate metabolism occurred in three overlapping phases. First, early in cooling, slight increases in VInv and β-amylase expression occurred. Second, at lower temperatures, large decreases in AGPase and GBSS expression were observed. Finally, when tubers reached 3–5 °C, large increases in β-amylase expression were observed, coinciding with large increases in sucrose in all genotypes and large increases in glucose and fructose in tubers with high VInv expression. Suppression of VInv expression did not alter the expression of β-amylase , AGPase , GBSS , or other genes, indicating that there was little or no feedback from reducing sugars to transcriptional control of carbohydrate metabolism. Invertase activity of WT tubers stored at 9 °C was comparable to that of WT tubers stored at 3 °C, but reducing sugars were markedly higher at the lower temperature. Taken together, these data support a model in which reducing sugar accumulation is controlled both by temperature-regulated changes in sucrose accumulation, resulting from increased starch degradation by β-amylase and decreased starch resynthesis by AGPase and GBSS, and by differences in VInv activity that persist throughout storage. [ABSTRACT FROM AUTHOR]

Food processing has significant simultaneous requirements of cooling, warm water and hot water. In order to reduce energy consumption and greenhouse gases emission, one type of NH 3 heat pump and two types of transcritical CO 2 heat pumps are proposed. These natural refrigerant heat pumps can supply not only cooling, but also warm water and hot water simultaneously. The characteristics and performance of the heat pumps are analyzed and simulated. Annual primary energy saving and annual operation cost saving are predicted for California, Wisconsin, New York, and Florida. Research results show that the maximum possible value of annual primary energy-saving rates using the CO 2 heat pumps ranges from 56% to 65%, and using the NH 3 heat pump is approximately 44%; the maximum possible value of annual operation cost saving rates using the CO 2 heat pumps ranges from 50% to 66%, and using the NH 3 heat pump is from 20% to 47%. [ABSTRACT FROM AUTHOR]

In order to achieve a rapid cooling rate and to increase the industrial yield of the products without compromising their quality attributes, immersion vacuum-cooling (IVC) is now widely applied for cooling of both small and large food items. However, the lower cooling rate compared with vacuum-cooling has initiated numerous studies to improve this technique. Substantial efforts, such as combination of IVC with other cooling methods, using different initial water temperatures, or employment of agitation during IVC, have been made to optimize cooling parameters while also maintaining quality properties and complying with strict food safety requirements. This review presents and discusses the IVC evolution and recent developments directed at the ready-to-eat meat products industry. The principle of IVC and its applications are discussed first. Then future prospects and suggestions are covered, especially for the cooling of ready-to-eat meat products. [ABSTRACT FROM AUTHOR]

The effect of tempering (20, 30 and 40 °C) and the cooling rate (0.5 and 2 °C/min) on physical properties and stability of whipping and whipped cream was investigated. Rheological behavior and light microscope observations showed that tempering at 30 °C and fast cooling created convenient condition for forming partial coalescence between fat globules in whipping cream. This special linkage helped to prevent serum leaking out of whipped cream when storing them at low temperature (4 °C). However, tempering at 20 °C would have been a more appropriate choice to stabilize structure of products through balance different types of partial coalescence in whipped cream during storage. [ABSTRACT FROM AUTHOR]

During the development of automation control of the bakery products cooling process using a 'cooler' it is necessary to build an integrated control system, which allows to optimize the process parameters in case of a variety of work situations that may occur in the bakery enterprise. The main task for control of such multifactorial object is to reach a certain temperature in the center of the product by maintaining the temperature of the cooling air near the surface of the loaf set in the limits t ± ▵ t, its velocity v ± ▵ v and humidity ϕ ± ▵ ϕ, and maintain the speed of the conveyor within Vc ± ▵ Vc using the frequency converters. Simultaneous exposure to multiple channels of control allows selecting the optimal combination of the cooling process control commands, yielding the product with necessary temperature and mass. Automatic control and regulation of the cooling process is based on the fact that the current value of the adjustable parameters in mismatch block is compared with predetermined values of the corresponding parameters, and the mismatch signals are formed, which are amplified to a value sufficient to trigger actuators that provide executive regulators. Novelty of the paper consists in the development of the process control system based on the mathematical model which allows calculating the temperature at the center of freshly baked products by the surface temperature of the product at any time of location in the cooling zone. Experiments were carried out on the bread made in the laboratory and cooled after baking, by natural and forced convection. Baking was conducted in a special parallelepiped tins with lids. Thus, the output product had a parallelepiped shape. Process of cooling by natural convection was implemented in a cooling chamber, which allowed to measure temperature and relative humidity. Temperatures changing in the center of the loaf and weight loss were recorded during the experiments. Cooling time was determined by the time required to achieve the temperature in the center of the loaf 30°C. On the basis of the experimental data a mathematical model and the computer system, allowing calculating the parameters of cooling and in time to make a regulatory influence on one of the control channels and thus optimize the process parameters were built. [ABSTRACT FROM AUTHOR]

Cooked restructured buffalo meat rolls prepared from restructuring process were stored at 4 ± 1°C in polyethylene terephthalate laminated with polythene pouches under vacuum packaging condition. The samples were evaluated for physicochemical parameters, microbial quality and sensory attributes at regular intervals of 0, 5, 10, 15, 25 and 30 days of storage. A significant decrease in pH, extract release volume values, was observed with increasing storage period. Overall days mean for moisture decreased with increasing storage period, however, no significant difference in overall days mean for moisture content was observed on from day 0 to day 30 of storage. A significant (P< 0.01) increase in thiobarbituric acid value and tyrosine value was observed with increase in storage period. Microbiological counts increased with the advancement of storage period. However, throughout the storage period, all microbial counts were within the acceptable limits of cooked meat products. Boiled restructured buffalo meat rolls did not show any symptoms of spoilage such as off odour and surface slime on day 30 of storage and were acceptable for sensory quality up to 30 days of refrigerated storage (4 ± 1°C) under vacuum packaging. Thus, the present study indicates that vacuum packaging could be used as a way to improve the shelf life of boiled restructured buffalo meat rolls without affecting the physicochemical, microbiological and sensory qualities of the products. [ABSTRACT FROM PUBLISHER]

Uniform suspension of particulates (salt or spices) in oil-based marinades requires a gel behavior of the matrix. This can be achieved by adding a solid fat to the liquid oil. Besides rheology, appearance and thermal stability are important for the utilization as marinades. The influence of solid fat concentration ( c = 2.5-5.5 wt%) and average cooling speed (1.4, 2.6, and 4.7 °C/min) on the functional properties of oil-fat gels from palm fat and canola oil was investigated. Oil-fat mixtures showed complex physiochemical behavior depending on the solid fat concentration and cooling rate. All samples had a shear-thinning behavior. Yield stresses and apparent viscosities increased at a constant cooling rate with increasing solid fat concentration. Frequency dependence of storage and loss modulus showed a transition from a viscous solution to a weak gel at c > 3.5 wt%. Samples at increasing cooling rates transitioned to weak gels at lower fat concentration (2.5 wt%). Mixtures became turbid and increasingly whiter as both solid fat concentration and cooling rates increased, which was explained by increased light-scattering by fat crystal aggregates. Results show the critical importance of proper formulation and preparation conditions on the functionality of oil-based marinades. [ABSTRACT FROM AUTHOR]

The antimicrobial impact of purified and natural sources of both nitrite and ascorbate were evaluated against Clostridium peifringens during the postthermal processing cooling period of deli-style turkey breast. The objective of phase 1 was to assess comparable concentrations of nitrite (0 or 100 ppm) and ascorbate (0 or 547 ppm) from both purified and natural sources. Phase II was conducted to investigate concentrations of nitrite (50, 75, or 100 ppm) from cultured celery juice powder and ascorbate (0, 250, or 500 ppm) from cherry powder to simulate alternative curing fonnulations. Ground turkey breast (75% moisture, 1.2% salt, pH 6.2) treatments were inoculated with C. perfringens spores (three-strain mixture) to yield 2.5 log CFU/g. Individual 50-g portions were vacuum packaged, cooked to 71.1°C, and chilled from 54.4 to 26.7°C in 5 h and from 26.7 to 7.2°C in 10 additional hours. Triplicate samples were assayed for growth of C. perfringens at predetermined intervals by plating on tryptose-sulfite-cycloserine agar; experiments were replicated three times. In phase I, uncured, purified nitrite, and natural nitrite treatments without ascorbate had 5.3-, 4.2-, and 4.4-log increases in C. perfringens, respectively, at 15 h, but

The new Food and Drug Administration (FDA) announcement makes it even more necessary to find alternatives to trans fats. The effect of cooling rate and temperature cycles on crystallization behavior and polymorphism of two solid fractions (stearins) obtained from a new variety of high-stearic high-oleic sunflower oil was studied by pulsed nuclear magnetic resonance (p-NMR), small-angle X-ray scattering (SAXS), and wide-angle X-ray scattering (WAXS) using synchrotron light and differential scanning calorimetry (DSC). Two stearins, hard (HS) and soft (SS), were crystallized in different processing conditions with the aim of obtaining the polymorphic forms required for different industrial applications. Data obtained from p-NMR studies showed that for both stearins, the maximum solid fat content decreased when crystallization temperature ( T) increased; besides, crystallization rate decreased for slower cooling rate and higher T. When HS was crystallized at 10 °C/min to 23 °C, it fractionated and two different β′ forms appeared together which was not suitable for processing purposes. SAXS and WAXS patterns indicated that slow cooling (1 or 0.5 °C/min) promoted crystallization of β′ polymorph and retarded nucleation and growth of β′ form. Slow cooling also promoted crystallization of β′ form at two T: 24 and 25 °C. When SS was kept isothermally at 17 °C for 90 min, three polymorphic forms appeared: α, β′, and β. Crystallization of the β polymorph was promoted with slow cooling and temperature cycles. DSC results were in agreement with X-ray findings. Selecting the proper thermal treatment, it was possible to obtain the β′ form for bakery products or the β form for chocolate production. [ABSTRACT FROM AUTHOR]

This paper presents the results of a cold chain field study in France in 2013 carried out in the framework of a European project named Frisbee. A comparison with the results obtained in a previous field study in France in 2002 was presented. These two studies enabled us to have a real picture of the cold chain because temperature monitoring was carried out in a manner not visible to operators and consumers. These studies concern the cold chain of chilled products from the production plant to storage in a domestic refrigerator. The Frisbee field study confirms the results observed in previous work that the most sensitive links are transportation after purchase and particularly storage in a household refrigerator. Despite the regulation imposed by the French authorities since 2002 to indicate the cold zone in refrigerators where sensitive products should be placed, the preservation of products at home is still problematic. [ABSTRACT FROM AUTHOR]

BACKGROUND Biogenic amines have gained a great deal of attention due to their toxic potential in humans. Carp is one of the most important freshwater fish species in China. Salt and sugar are capable of preserving food. There is a limited amount of information on the changes of biogenic amines in freshwater fish influenced by salt and sugar. This study aimed to detect the changes in biogenic amines, sensory attributes, total volatile basic nitrogen ( TVB-N) and total viable counts ( TVC) of carp influenced by different concentrations of salt and sugar stored at 4 °C. RESULTS TVB-N and TVC increased with storage time, which was in accordance with the changes of sensory scores. The eight biogenic amines were detected in fresh carp. Putrescine and cadaverine were the main biogenic amines found in carp fillets stored at 4 °C; they had a significant ( P < 0.05) correlation with TVB-N. CONCLUSION Salt processing was found to inhibit the increase of TVB-N, TVC, putrescine and cadaverine in carp. High salt concentration had a positive effect on extending the shelf-life of the carp, compared to low salt concentration. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Lentil is an important staple food crop in many regions and is a good source of protein and various micronutrients. Lentil also contains raffinose family oligosaccharides (RFO), resistant starch (RS), and other prebiotic compounds essential for maintenance of healthy gastrointestinal microflora. However, there is a lack of information about concentrations of prebiotics in commercially available, cooked, and processed lentil market classes. This study assessed concentrations of RFO and RS in two commercially available lentil market classes (medium green and small red) and determined changes associated with dehulling, cooking, cooling, and reheating. Mean total RFO concentrations ranged from 5.5 to 6.1% in raw lentils. Total RFO concentration decreased from raw to reheated seeds in two of the four lentil products: whole red (6.1–4.9%) and whole green (5.5–4.3%). Mean RS concentrations in raw, cooked, cooled, and reheated lentil (3.0, 3.0, 5.1, and 5.1% (dry weight), respectively) clearly demonstrate cooling-induced synthesis of RS from gelatinized starch. These results highlight the impact and importance of processing techniques on lentil nutritional quality for both consumer and food industry use. [ABSTRACT FROM AUTHOR]

This study aimed at investigating the effects of amylose content (AC) of 0.12–19.00% w/w on dry basis, cooling rate (1, 3, 5, and 9 °C/min), and aging time (24, 48, and 72 h) on structure, physical properties and sensory attributes of rice starch-based puffed products. They had an influence upon the crystalline type, and the relative crystallinity (RC). The thermal and physical properties of starch gels were also determined. Amorphism was found for starch gels with 0.12% AC. The polymorphisms (B and V) and differential scanning calorimetric endotherms were found for those with AC ≥4.00%. The RC, retrogradation enthalpy (ΔH r ) and gel hardness increased with AC and aging time. The cooling rate did not affect RC, but increased ΔH r and gel hardness. The higher AC and aging time resulted in higher hardness, fracturability, crispiness and bulk density, but lower expansion ratio and less oiliness of the puffed products. The hardness, fracturability, crispiness and bulk density of puffed products were well correlated with the RC of starch gel. [ABSTRACT FROM AUTHOR]

An experimental study was conducted to determine the performance of two evaporative cooling systems, as well as the gradients of temperature and humidity along a greenhouse. The first system was the cooling unit, (CU) compared with the traditiona l fan-pad one, (F-P). The cooling unit was connected with two perforated ducts inside the greenhouse. The air temperatures and relative humidities on the longitudinal axis were measured outside and just after leaving the media and at each one meter from the pad media. They were also, measured in the traverse axis parallel to the pad media at distances 0.5, 1.5, 2.5 and 3.5 m from the edge of the greenhouse. A steady state mathematical model was modified to predict the greenhouse air temperature according to the state of the air just leaving the cooling media. According to the experimental results, the non-uniform temperature changes were observed along the greenhouses for the two systems. The average temperatures of the CU greenhouse were 27.9, 30.4, 33.2, 29.1 and 27.9 o C for outside ambient temp eratures of 28.7, 32.4, 35.4, 32.1 and 29.4 o C, respectively. The ranges of temperature gradient inside the CU greenhouse were 2.1, 2.1, 2.2, 2.2, and 2.1 o C. While in the F-P greenhouse, they were 5.9, 7.4, 8.2, 5.9 and 6.1 o C for the same ambi ent temperatures. The average air temperature entering to greenhouse was approximately 6.82 and 7.09 ºC lower than the outside air temperature for CU and F-P systems. The greenhouse of CU system was higher in the relative humidity than F-P one. The average relative humidities were 69.0 and 61.8% for the CU and F-P greenhouses, respectively, with increase percent 12.38%. The averages CU efficiencies were 77.55% and 74.79% in the first and second days, respectively, while they were 72.97% and 70.19% for the same days for F-P system. Consequently, the CU system was averagely more efficient than the F-P system by 6.29% and 6.58%. The water flow rate of the two systems to permit optimum wetness and air saturation were 5.6 and 6.5 L/min for the CU and F-P evaporative cooling systems, respectively. The saving percentage in water circulation was 16.1% for the CU system. The total yield per plant was 6.24 and 5.48 kg/plant for the CU and F-P systems, respectively. The CU system increased the yield per plant with 13.82% over the F-P system. [ABSTRACT FROM AUTHOR]

Flowrate and distribution of air is a critical design factor in the cooling, refrigeration and drying of horticultural food products. These operations rely on a constant supply of air distributed throughout bulk arrangements of the produce. Local distribution of the air is critical to optimising the design and efficiency of these processes. Identification of the key parameters affecting the airflow distribution has been done either experimentally (using intrusive point-wise or bulk measurement techniques) or numerically. The detailed information provided by the use of computational fluid dynamic models has facilitated unique opportunities to investigate alternative system designs, without the need for expensive and time consuming experiments. This study provides a review of the techniques available to measure airflow (thermal and rotatory vane anemometry, pressure differential devices, tracer gases, LDA and PIV). Their advantages and disadvantages (accuracy, resolution, application range, cost, and ease of use) as well as their application in the validation of numerical models are reviewed. The novel and scientifically based design guidelines developed by a better understanding of the airflow behaviour within the system for each of the operations under study are also presented. [ABSTRACT FROM AUTHOR]

Effects of different pressure reduction rates and liquid agitation (523 rpm) on sausage successful rate, cooling time, cooling loss, texture properties, chemical and physical parameters were analysed by ANCOVA. Tested linear pressure drop rate from 320 mbar to 50 mbar was 20 (L 20), 30 (L 30), or 40 (L 40) mbar/min for artificial casing sausages (ACS) and 60 (L 60), 80 (L 80), or 100 (L 100) mbar/min for natural casing sausages (NCS). From 50 mbar until 6.4 mbar, 5 mbar/min was used for both casings. NCS were more suitable than ACS for IVC. The recommended pressure reduction rate was 30 mbar/min for ACS and 60 mbar/min for NCS. ACS under 30 mbar/min with agitation (LA 30) presented significantly higher texture property values than that without agitation (L 30) ( P < 0.05 ). Cooling time (to 4 °C) of NCS under 60 mbar/min and agitation (LA 60) was significantly shorter than that without agitation (L 60) ( P < 0.05 ). This study could assist meat processors or manufactures when choosing a suitable pressure drop rate for different types of sausages. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine the effect of rapid (RC) and conventional (CC) chilling with achilles(AS) and pelvic (PS) suspension on the meat quality of M. Longissimus dorsi. Twenty lamb carcasses were randomly allocated immediately prior to slaughter to the two experimental groups which were subjected to four different treatments. In the first group, carcasses were suspended from the Achilles tendon. Right sides (RC/AS; n=10) were rapidly chilled, while the left sides (CC/AS; n=10) were conventionally chilled. In the second group, the carcasses were re-hanged from the pelvic bone. Right sides (RC/PS; n=10) were rapidly chilled whilst the left sides (CC/PS; n=10) were conventionally chilled. Meat quality was evaluated by measuring the water holding capacity (WHC), cooking loss (CL), surface colour and shear force (SF). As a result, CC accelerated the rate of pH decline while RC increased the temperature decline. RC reduced CL and WHC values. PS had no impact on WHC, CL and color of steaks, but decreased the SF values on the 7th days of post-mortem. In conclusion; PS is a useful method for improving tenderness during storage period and the disadvantageous effect of RC on SF could be equalized by using PS. [ABSTRACT FROM AUTHOR]

Data are lacking on the temperature changes of food during transport without the use of refrigerated trucks. The purpose of this study was to evaluate the ability of several insulated and noninsulated containers with or without frozen gel packs to keep perishable and refrigerated foods within the temperature safe zone in relationship to duration of transport. The study was designed to duplicate the practices exhibited by customers purchasing perishable food products from a cash-and-carry business. Approximately 40 perishable food items were evaluated. Four types of containers were tested: a mylar foil bag, a commercial insulated bag, a generic insulated bag, and a commercial insulated blanket. Mixed foods were placed into these containers with or without frozen gel packs, transported in unrefrigerated vehicles, and monitored for 4 h for temperature changes. Two environmental temperatures, room temperature of 21.1°C and a stress temperature of 37.8°C, were evaluated. The internal temperature and surface temperature of the food products in these containers increased slowly but remained well below the U.S. Food and Drug Administration Food Code requirements. The various containers were similar in their ability to retain coolness. The presence of frozen gel packs dramatically enhanced the cold-holding capacity of the containers. The temperature of foods increased more rapidly when stressed in a heated environment. The containers tested used with the frozen gel packs can keep the surface and internal temperatures of various perishable foods (starting at 4.4°C or less) within the Food Code recommendation of under 21.1°C for 4 h. Cash-and-carry businesses should strongly encourage their retail customers to utilize these containers with frozen gel packs to safely transport perishable foods. [ABSTRACT FROM AUTHOR]

The study investigated the use of impingement methods for cooling of fruits and vegetables. Raw materials were cooled in air at 0°C temperature flowing from nozzles of 0.02 m diameter with speed in the range of 10-51 ms-1 and for comparing, in the water at the same temperature. Raw mass change, value of heat transfer coefficient in the system and the cooling time were analyzed. The mass losses are dependent on air velocity at the nozzles exit, increase in the cooling air velocity permits a reduction in the losses. The mean value of heat transfer coefficient were found within the 12-44 W(m2 K)-1 range. It was found that the impingement method can be used for rapid cooling of fruits and vegetables, characterizing the process parameters comparable to the cooling of water. [ABSTRACT FROM AUTHOR]

Highlights: [•] The new package designs showed an improved cooling rate and cooling uniformity. [•] The new package designs reduce the energy load due to their lower aerodynamic resistance. [•] Package design is a cost-effective way for improving forced-convective precooling. [•] Basic information on the packages was obtained to guide future cold-chain design decisions. [ABSTRACT FROM AUTHOR]

Abstract: The cook-chill operation, a widely used process within central cooking facilities, implies that cooked dishes have to be quickly cooled down immediately after cooking in order to prevent any food-borne diseases due to Clostridium perfringens. The food service operators are obliged to validate the efficiency of the cooling process in the context of their HACCP plan. To perform this cooling process, they can either ensure compliance with some reference criterion (maximal cooling duration) or demonstrate that the cooling operation is safe by carrying out prior tests. This document presents an experimental method to validate the sanitary efficiency of the cooling process. In the studied kitchen the food was cooked and, successively, distributed into plastic containers, cooled down in blast-chiller and then stored in cold room. The tests consisted in monitoring food temperature at the center of the containers from the end of cooking until the beginning of cold room storage. The measurements were performed during 6 cycles of food preparation. From the monitored time–temperature profiles, thermal cooling equations were established for modeling. Each parameter of these thermal equations was linked with a distribution fitted with the experimental data. Then these thermal equations were coupled with predictive microbiology equations. A probabilistic calculation of the C. perfringens potential growth was carried out by using @Risk software. The proposed method required only simple monitoring equipments and could be easily implemented in central kitchens under the usual working conditions. The cooling conditions in the studied kitchen could be considered as satisfactory because the calculations give only a 0.4% probability that the C. perfringens potential growth was equal or greater than 1 log10 cfu/g. [Copyright &y& Elsevier]

Three different cooling methods: commercial cooling and immersion vacuum cooling (IVC) with two different initial water temperatures (20 °C and 80 °C) were applied to cooked sausages. Linear pressure drop rate of 60 mbar/min with agitation was employed in the current experimental trials. Chemical (moisture and pH) and quality (colour and microbial analysis) parameters after cooling were monitored during 29 days of cold room storage (4 °C) and the shelf-lives of the sausages were determined. Results showed that IVC with cold water (IVCC) could achieve not only rapid cooling time to 4 °C (31 min), compared to IVC with hot water (IVCH) (41 min) and commercial cooling (251 min), but also a longer shelf-life. pH of IVCC samples was more stable during cold room storage than the other cooling methods. Core colour of IVCH sausage turned to be darker with time; all the samples became slightly redder after 15 days of storage. It was concluded that IVC could surpass commercial cooling method in terms of cooling time and shelf-life of the sausages. Additionally, IVCC (if the tap water used was hygienic enough) did not introduce external detrimental bacteria and possessed a higher cooling rate than IVCH without compromising the quality properties. [ABSTRACT FROM AUTHOR]

Highlights: [•] CFD models of 1-MCP transport based on detailed geometries of boxes and individual fruit have been developed. [•] Models and measurements showed uniform distributions of the gas in air throughout the treatment period. [•] The level of air circulation in room cooling process is sufficient to uniformly distribute the 1-MCP in the air. [•] Wooden boxes significantly deplete the active substance from the treatment atmosphere. [•] The study suggests dose reduction. [Copyright &y& Elsevier]

ABSTRACT The aim of this work was to investigate the integration of the cooking and vacuum cooling of potatoes in a single vessel. For integrated process of water immersion cooking followed by vacuum cooling with the samples immersed in the cooking water (ICk + IVC), water gain of about 3.4% was observed, instead of water loss. However, twofold longer cooling times were necessary when compared with immersion cooking followed by vacuum cooling performed after draining of the water cooking (ICk + VC) and for steaming cooking followed by vacuum cooling (SCk + VC). Water loss of approximately 15% was observed for ICk + VC and SCk + VC processes. On the other hand, weight losses can be compensated by a rehydration stage, immerging cooked-cooled samples in a small amount of sterile cold water. The maximum compression force of the samples processed by ICk + VC was twofold higher than for samples processed by ICk + IVC and SCk + VC processes. PRACTICAL APPLICATIONS For the preparation of ready-to-eat meals, the use of cooked vegetables is common. These products are often cooled by slow air cooling, air blast or water immersion cooling. Many studies concerning new technologies for food cooling have reported the viability of using the vacuum cooling technique to reduce the cooling time. In this way, the objective of this work was to investigate the possibility of integrating cooking and cooling of potatoes in a single vessel using the vacuum cooling technique. The achieved results demonstrated that the integrated process of cooking and vacuum cooling of potatoes in a single vessel is a viable alternative for processing such kind of food. [ABSTRACT FROM AUTHOR]

Highlights: [•] Optimization of hard candy cooling stage. [•] Development of a NLP mathematical model to obtain optimal operating policies. [•] Quality constraints and operating cost are considered. [•] Operating conditions and production planning are obtained for three operating modes. [•] The model is useful to be applied in other hard candy lines. [Copyright &y& Elsevier]

This study investigated the influencing factors of the Stirling refrigeration bench on the cooling and churning functions and applied the Stirling refrigeration technology to butter processing. Results showed that both refrigerant volume and mechanical vibration frequency have significant effects on the cooling effect. Optimal cooling effect was achieved for the refrigeration bench with 50 mL refrigerant volume and 12.5 Hz vibration frequency. The temperature of cold end decreased 34.5 ± 2.3 °C after 420 s of refrigeration. Given the parameters mentioned above, the fastest butter formation was achieved when the initial fat content in the cream was 25 %. The quality of the resulting butter is better than the resulting butter formed by using creams with 15 or 35 % initial fat contents. The results provide certain theoretical references for the application of the Stirling refrigeration technology to the butter processing industry. [ABSTRACT FROM AUTHOR]

Knowledge of cheese density is necessary to accurately predict heat exchange rate occurring during cheese curd cooling or cheese processing, freezing and thawing. Cheese density data are poor in literature. True density of 22 different cheeses was measured by the water displacement method. Linear equations able to predict cheese density from its components mass fraction have been elaborated and validated. The best fit between measured and predicted values was obtained when all the major cheese components were considered in the equation. Also, equations based only on nonfat total solids or moisture and fat content gave a good prevision, resulting in an alternative to the universal formula based on components volume fraction that overestimates cheese true density, if air content is not taken into account. The proposed equations may become a powerful instrument to correctly predict true density and to improve accuracy of heat exchange prediction models. Practical Applications Equations were developed to quickly calculate soft, semihard and hard cheese true density on the basis of nonfat total solids or moisture and fat cheese content. Cheese density data are poor in literature and often data do not differentiate true from apparent density. Proposed equations are beneficial to researchers in food heat exchange modeling and to industry (e.g., processed cheeses, cheese cooling, freezing and thawing), because their use makes possible to estimate true density using data normally given by routine and not expensive analyses (moisture and fat cheese content), saves time and/or money compared with direct density measurement or application of the universal formula based on the determination of all the main food components. [ABSTRACT FROM AUTHOR]

The present study concerns the numerical analysis using the finite volume method, of laminar forced convection flow of a viscoplastic fluid. The flow takes place in a circular pipe maintained at uniform wall temperature. The fluid consists of the sloe fruit juice with low pulp and pectin contents which obeys the rheological model of Bingham. The Nusselt number and the friction factor when both viscous dissipation and variability of the viscosity upon temperature for heating and cooling cases are taken into account are calculated and compared to those obtained for an isothermal flow when viscous dissipation is neglected. The results show that neglecting both viscous dissipation and the temperature dependency of viscosity leads to underestimate heat transfer and pressure drop. Practical Applications Heat transfer and pressure drop are important parameters in industries dealing with fluids, especially food industry. These parameters are used to predict the fluid's flow behavior and to estimate energy needed to for heating and transporting. A miscalculation of these parameters, when neglecting some factors in calculation such as the temperature dependency of viscosity or viscous dissipation, may result in significant errors in equipment design. The results obtained from the present study give an idea on how much heat transfer and pressure drop are underestimated when neglecting either the viscous dissipation or the temperature dependence of the fluid viscosity or both of them, when dealing with viscoplastic fluids such as fruit juices. [ABSTRACT FROM AUTHOR]

ABSTRACT The objective of this study was to investigate critical parameters affecting oil absorption and provide promising clues for reducing oil absorption in the deep-fat fried potato products. Driving forces of oil absorption in deep-fried potato cylinders were analyzed during a post-frying cooling. Results revealed that a pressure difference ( Patm − Pv), which was formed by vapor condensation, played a key role in the oil uptake into microstructure of the fried potato products. Based on the experiments conducted in the different vacuum environments, it was found that less oil was absorbed by the potato cylinders when they were cooled under 80 kPa after frying, in which a delayed initiation of oil uptake and a reduced driving force for oil absorption were noticed. Therefore, lowering the pressure difference ( Patm − Pv) with pressure-vacuum method can change the equilibrium existing between oil uptakes and adhesion, which promoted the oil drainage at the early stage of cooling period and led to a low amount of oil uptake into the fried food. PRACTICAL APPLICATIONS These results can provide a reference for reducing oil uptake of deep-fat frying process in the food industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Milk and dairy products are natural sources of B group vitamins in the human diet. This study was carried out to compare the ability of probiotic and conventional microorganisms of yogurt to influence the status of vitamin B2 (riboflavin) and vitamin B3 (niacin) during refrigeration. METHODS: After preparation of conventional and probiotic yogurt, all samples were stored at 4°C, and the content of B2 and B3 vitamins was assessed on first, third and seventh day of refrigeration. Vitamins B2 and B3 were analyzed in samples using high-performance liquid chromatography followed by fluorescence detection and ultraviolet detection, respectively. Data was analyzed using SPSS version 18 (SPSS Inc., Chicago, USA). RESULTS: Vitamin B2 content of probiotic yogurt samples was significantly higher than the control samples on all experiment days (P< 0.05). Significant differences between content of vitamin B3 in conventional and probiotic yogurt were found only on the seventh day of refrigeration (P< 0.05). CONCLUSION: This study showed that using probiotic strains from yogurt manufacturers might provide higher B2 and B3 vitamin content provided yogurt is refrigerated for storage. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of different pasteurization treatments on sensory characteristics and content of vitamin C of four fruit juices: Blackberry cv. Castilla (MC), Mango cv. Costeño (MAC), Orange cv. Valencia (NV) and Tree tomato cv. Tamarillo (TA). The results showed that the suitable pasteurization process, defined as that who showed lack of peroxidase (POD) activity, measured qualitatively for each juice, was 80°C for 120 seconds (MC), 80°C for 90 seconds (MAC), 75°C for 90 seconds (NV), and 80°C for 90 seconds (TA); the effect of processing on the color, smell and taste of juices was assessed using sensory analysis by a trained panel and revealed that there were no significant differences (p<0,05) among characteristics evaluated before and after heat treatment. The pasteurization treatment-induced losses of vitamin C, were quantified using Mohr method, exhibited values of 84,67% (MC), 89,82% (MAC), 99,43% (NV) and 87,72% (TA). The treatment applied, prolonged the shelf life of the juice from 10 to 12 days at refrigeration temperature, without appreciable changes in sensory characteristics. [ABSTRACT FROM AUTHOR]