Effect of processing conditions on quality of green beans subjected to reciprocating agitation thermal processing

The effect of reciprocating agitation thermal processing (RA-TP) on quality of canned beans was evaluated in a lab-scale reciprocating retort. Green beans were selected due to their soft texture and sensitive color. Green beans (2.5 cm length × 0.8 cm diameter) were filled into 307 × 409 cans with carboxylmethylcellulose (0–2%) solutions and processed at different temperatures (110–130 °C) and reciprocation frequency (1–3 Hz) for predetermined heating times to achieve a process lethality (F_o) of 10 min. Products processed at higher temperatures and higher reciprocation frequencies resulted in better retention of chlorophyll and antioxidant activity. However, high reciprocation frequency also resulted in texture losses, with higher breakage of beans, increased turbidity and higher leaching. There was total loss of product quality at the highest agitation speed, especially with low viscosity covering solutions. Results suggest that reciprocating agitation frequency needs to be adequately moderated to get the best quality. For getting best quality, particularly for canned liquid particulate foods with soft particulates and those susceptible to high impact agitation, a gentle reciprocating motion (~ 1 Hz) would be a good compromise.     

Evaluating the impact of thermal and pressure treatment in preserving textural quality of selected foods

A study was conducted to evaluate the efficacy of various combinations of pressure and thermal treatments in preserving textural quality of selected foods. Carrot, zucchini, apricot, red radish, and jicama were used as test samples. Pressure-assisted thermal processing (PATP; 600 MPa, 105 °C), high-pressure processing (HPP; 600 MPa, 25 °C), and thermal processing (TP; 105 °C, 0.1 MPa) experiments were conducted. Role of pressure (600 MPa) in preserving product quality while simultaneously (PATP) or sequentially (HPP-TP) exposed to elevated process temperature (105 °C) was also compared. Instrumental puncture, shear force, color and sensory analyses were utilized to compare the influence of the various process treatments. A crunchiness index (CI), relating product puncture force and stiffness, was able to characterize the severity of the process treatments on various products tested. Among the treatments, TP was the worst at retaining texture, but HPP-TP improved texture retention. In comparison to TP alone, PATP better retained texture and color. Jicama was least influenced by the treatments as compared to products tested. Process treatments investigated degraded the textural quality of zucchini and apricot. Instrumental CI results were also in agreement with the sensory data of carrot, red radish and jicama samples.     

Optimizing Thermal Process for Canned White Beans in Water Cascading Retorts

Based on thermal degradation kinetics and heat transfer expressed as the Ball formula method, a simplified approach was used to optimize sterilization processes for thermal softening of white beans (Phaseolus vulgaris, subsp. nanus Metz., variety Manteca de Leon) Constant retort profiles in a still and end-over-end rotary water cascading retort (Barriquand Steriflow) were used. Quality attributes of beans processed at the optimum were evaluated by a trained taste panel and by a tenderometer. Both approaches could distinguish (P<0.01) between attributes of products from optimal rotary and still processes. End-over-end rotation resulted in faster heat penetration and better quality retention of beans. Texture of white beans processed at 4° or 8°C from the optimal temperature could be distinguished (P<0.01) by the sensory panel and by the tenderometer.     

Simultaneous optimization of heat transfer and reciprocation intensity for thermal processing of liquid particulate mixtures undergoing reciprocating agitation

Simultaneous optimization of heat transfer and reciprocation intensity (RI) was carried out for reciprocating agitation thermal processing (RA-TP) of liquid-particulate foods. Heat transfer data under various processing conditions (temperature, frequency, and headspace) and product properties (liquid viscosity, particle concentration, and particle density) during RA-TP were utilized to develop a composite model using quadratic stepwise regression analysis. Heat transfer coefficients were maximized individually and simultaneously with minimal RI using multiple-variable optimization. High RI (37–45 ms^− 2) was recommended to maximize heat transfer alone, whereas lower RI (16–19 ms^− 2) was found optimal for simultaneous optimization of heat transfer & RI. Product formulations containing low viscosity liquids filled with 23–27% volume of particles with density of 1130–1350 kg/m³ were found most desirable for maintaining good quality under RA-TP. Optimal conditions were also reported for applying RA-TP under different operating temperatures, liquid viscosities, particle concentrations and particle densities.Industrial significanceReciprocating agitation of containers is receiving interest from thermal processing industry for enhancing product quality. The aim of this study was to optimize the use of reciprocating agitation thermal processing for processing particulate liquid foods. This study attempts to predict optimal conditions of processing conditions and product compositions for reciprocating agitation thermal processing. Multi-variable optimization based on data from multiple experimental designs is conducted in this study, which will be directly relevant to be used by industry seeking to employ reciprocating agitation thermal processing.     

Effect of different moisture equilibration process on the quality of apple chips dried by instant controlled pressure drop (dic)‐assisted hot air drying

Moisture equilibration process (MEP) is an important process before controlled pressure drop (DIC) drying to obtain greater products quality and avoid producing bubbles. The aim of this work was to study the effect of MEP on the quality of apple chips dried by instant controlled pressure drop‐assisted hot air drying (DIC‐AD). After predrying by AD, four types of moisture equilibration solutions were applied to equilibrate the moisture of apple chips before DIC. The quality of apple chips equilibrated in water for 10 min was superior to those for 30 and 60 min with better color, brittleness, hardness, puffing degree (PD), and microstructure. Sugar solutions showed positive effect on brittleness and hardness, PD, and soluble solids of apple chips. In addition, calcium chloride was beneficial to the color of apple chips, and the product showed good rehydration and PD possibly due to the reaction between pectin and calcium ions.

Practical applications

Instant controlled pressure drop (DIC) was a new sort of united drying method that can combine with other drying technology, such as hot air drying and freezing drying. In practical production, apple slices are usually dried to low moisture content for long time storage and regained appropriate moisture content before drying. After predrying, moisture equilibration process (MEP) is an important process before DIC drying which made water homogenous distributed in the sample to obtain greater products quality and avoid producing bubbles during DIC drying. In this study, MEP with different solutions including water, fructose syrup, maltitol, and calcium chloride were performed before DIC drying, and the changes of physiochemical properties of dried products were studied. Based on the analysis of experimental results, predried apple slice equilibrated in water for 10 min, 10% fructose syrup and 30% maltitol solution might produce apple chips with better quality.     

COFFEE DRYING IN A ROTARY CONDUCTION-TYPE HEATING UNIT

Parchment coffee (Arabica) was dried from an initial moisture content of about 90% to 10% dry basis (db) in a recirculating rotary conduction type heating unit at controlled plenum temperatures of 100, 120 and 140C or controlled product temperatures of 50, 60, and 70C. the temperature of the plenum or moving beans could be maintained at specified levels with small variations during coffee drying experiments. the color and specific gravity of coffee beans exhibited minimum changes as a result of drying operations. the susceptibility of coffee beans to breakage decreased with the lowering of moisture and attained minimum values in the moisture content range of 20 to 30% db. the breakage susceptibility increased sharply with further reduction in moisture content. A drying model, which considered product temperature‐time history alone under different operating conditions, estimated the change in moisture content adequately. Such a model could be used for computer‐based control of the coffee drying process.     

Toroidal cans for thermal processing of liquid and solid-liquid mixtures under static and end-over-end rotation

Heat transfer is mainly influenced by can geometry and product type. Agitating retorts have been widely used for heat transfer for liquid foods. Since convective heat transfer coefficient is high, this leaves the container geometry the only option to increase heat transfer rate and decrease process time for quality improvement. This is even valid for agitation processes due to applied limitation in the rotation rates. A recent innovation for this purpose was the introduction of toroidal cans. Therefore, the objective of this study was to investigate the potential of novel toroidal can geometries in processing of liquid and solid-liquid mixtures during an end-over-end (EoE) rotation canning process to decrease process time and improve product quality. For this purpose, canning was carried out using custom built toroidal cans processed in a horizontal multi-process EoE retort system. The products processed were distilled water, black salsify-water mix and tomato - based mushroom sauce. Temperature changes of the products were recorded during the EoE canning, and the results were analysed for the heating rate. Combination of toroidal cans and EoE agitation process resulted in a significant reduction in the process time depending upon the viscosity of the product. The results demonstrated the effect of product viscosity and toroidal can geometry on reducing process time. These results were shared with industrial partners and stakeholders to evaluate the potential implementation at industrial scale for expected increased energy efficiency with improved product quality.     

Quality Evaluation of Pinto Beans and Green Beans Canned in Two Large Reusable Containers

ABSTRACT: As an alternative to standard metal cans, 2 large-scale, reusable containers were constructed with volumetric capacities 3.6 to 3.8 times greater and process times 1.36 to 2.05 times longer than a nr 10 can. Effects of increased process time on product quality were measured by conducting objective color and texture evaluations on green beans and pinto beans canned in both containers. Green beans and pinto beans had comparable texture profiles to beans processed conventionally in nr 10 cans. The color of green beans also was comparable; the color of pinto beans was darker, possibly due to contact with the metal container. Color and texture differences were minimal between inner and outer product layers.     

Modelling of cooking-cooling processes for meat and poultry products

Traditional cooking‐cooling of processed meat and poultry products is industrially carried out in smokehouses or autoclaves. A mathematical model was developed to simulate these operations. Equations, describing heat transfer and thermal destruction of micro‐organisms and quality characteristics, were solved numerically. The model was validated experimentally for heat transfer and energy consumption and was used to perform a sensitivity analysis. Input variables were: process time (PT), smokehouse temperature (T_SH), bologna size (diameter, D and height, H), surface heat transfer coefficients (h_heat and h_cool), product thermal diffusivity (α_heat and α_cool). Output variables were: product core temperature (T_c), core and volume‐average lethality (P_cm and P_vm) and cook (C_c and C_v) values as well as surface (Q_s) and volume‐average (Q_v) quality retention, total specific energy consumption (En) and energy efficiency (Ce). Multiple linear regression models were developed to predict C_c and C_v from five inputs and used to obtain acceptable deviation ranges.     

Heat transfer phenomena during thermal processing of liquid particulate mixtures—A review

During the past few decades, food industry has explored various novel thermal and non-thermal processing technologies to minimize the associated high-quality loss involved in conventional thermal processing. Among these are the novel agitation systems that permit forced convention in canned particulate fluids to improve heat transfer, reduce process time, and minimize heat damage to processed products. These include traditional rotary agitation systems involving end-over-end, axial, or biaxial rotation of cans and the more recent reciprocating (lateral) agitation. The invention of thermal processing systems with induced container agitation has made heat transfer studies more difficult due to problems in tracking the particle temperatures due to their dynamic motion during processing and complexities resulting from the effects of forced convection currents within the container. This has prompted active research on modeling and characterization of heat transfer phenomena in such systems. This review brings to perspective, the current status on thermal processing of particulate foods, within the constraints of lethality requirements from safety view point, and discusses available techniques of data collection, heat transfer coefficient evaluation, and the critical processing parameters that affect these heat transfer coefficients, especially under agitation processing conditions.     

Effects of pretreatment ultrasound bath and ultrasonic probe,in osmotic dehydration,in the kinetics of oven drying and the physicochemical properties of beet snacks

Osmotic dehydration and ultrasound are pretreatments used in order to reduce costs and processing time in the drying of food. We investigated the effect of the ultrasonic bath and an ultrasonic probe in osmotic solution, as a pretreatment of the drying process in an oven, for beet snacks. Different conditions of pretreatments (TP: ultrasonic probe treatment; TB: ultrasonic bath treatment) were performed and analyzed for water loss (WL) and solid gain (SG). After the snacks were ready, we evaluated the drying kinetics, aw, Brix, color, texture, and anthocyanin content. No difference was observed between treatments for SG and WL. The pretreatments TP5, TP10 and TB20 decreased by 22.2% the drying time in the oven. Regarding the snacks, there was no difference in texture. The colors of TP5, TP10, and TB10 were similar to the control, as well as the a_w value of the TP5 and TP10. The TP5 had the highest anthocyanin content. The use of ultrasound probe in osmotic solution for 5 min, as a predrying treatment, is a viable technology as it reduces pretreatment and drying time without impairing the quality of the final product.

Practical applications

The use of ultrasound as a pretreatment in the drying of fruits reduces the drying time. Drying is an important process in obtaining new products, in addition to increasing shelf‐life.     

Identification of E-Hex-3-enal as an important contributor to the off-flavour aroma in kiwifruit juice

Mechanical damage to dry kidney beans was assessed using hot and cold water soak-tests at 20 and 80°C, respectively. Damage was revealed as the middle lamella dissolved and the seed coats were released with zero order kinetics. Damage exposed in soak-tests had no cause-and-effect relationship to damage found in the cans after thermal processing. However, significant correlations were found between both kidney bean density and seed coat weight, and the proportion of damaged beans in the can after processing (P <0.01). The proportion of damaged beans found in the can after thermal processing increased significantly when the ratio of the seed coat weight to bean volume ratio was < 10 g ml^?1. These two simple measurable parameters offer potential for predicting canning quality of kidney beans.     

Evaluation of the instrumental quality of pressure-assisted thermally processed carrots

ABSTRACT:  This study was conducted to compare the effectiveness of pressure-assisted thermal processing (PATP) in preserving the texture, color, and carotene content of carrot cylinders in the pressure range of 500 to 700 MPa and the temperature range of 95 to 121 °C. The effectiveness of PATP was compared with that of conventional thermal processing (TP) by matching carrot preprocess temperature history. Results indicated that under comparable process temperatures (up to 105 °C), PATP retained the carrot quality attributes such as color and carotene content better than TP. However, process and preprocess thermal history at 121 °C greatly influenced carrot textural change and pressure protective effects were less pronounced. This study demonstrated that PATP has the potential to produce low-acid foods with a relatively better quality than TP.     

Extrusion-cooking to improve the animal feed quality of broad beans

Extrusion-cooking of broad beans with a single-screw extruder has been investigated. Attention was focused on process requirements as well as on the nutritional effects of extrusion-cooked broad beans in a chicken feed formulation. The optimal thermal process conditions required for a product of good quality from broad beans are given. Feeding trials with diets containing extrusion-cooked broad beans were carried out and it was found to be possible to replace at least 60% soya in a chicken ration. This work demonstrates that extrusion-cooking of broad beans is an acceptable process for animal feed in respect of protein quality, particularly in countries where Vicia faba are commonly cultivated.     

Effect of high‐pressure processing on immunoreactivity,microbial and physicochemical properties of hazelnut milk

This study investigated the effects of high‐pressure processing (HPP) and thermal processing (TP) on the overall quality attributes of hazelnut milk. HPP achieved the same microbial safety as TP, and the pH, °Brix and sugar contents were maintained at the levels of fresh hazelnut milk. Although HPP caused colour changes, the ?E was smaller than that of the TP sample. Increasing pressure significantly decreased the immunoreactivity of the hazelnut milk by 70%, while simultaneously reducing the levels of essential and non‐essential amino acids and chemical score (CS) and the essential amino acid index (EAAI) values. However, neither HPP nor TP significantly affected the fatty acid composition of hazelnut milk. HPP retained higher total phenolic and flavonoid levels of the hazelnut milk, with a better antioxidant capacity than TP samples. Thus, the HPP maintained microbial safety during cold storage, and physicochemical properties of the treated hazelnut milk were not significantly different from those of the fresh hazelnut milk.     

A review on egg pasteurization and disinfection: Traditional and novel processing technologies

Salmonella Enteritidis is a pathogen related to many foodborne outbreaks involving eggs and egg products. Regulations about whether eggs should be pasteurized are very different and inconsistent worldwide. In the United States, eggs are not required to be pasteurized. Hence, less than 3% of the eggs in the country are pasteurized. The standard pasteurization method (57°C, 57.5 min) uses a long thermal process that increases the cost of the product and affects its quality. Foodborne outbreaks can be reduced if eggs are properly pasteurized to inactivate Salmonella spp. However, the technology to pasteurize eggs needs to offer a faster and more reliable method that can be scaled up to industry settings at a low cost and without affecting product quality. Several novel technologies have been tested for eggshell disinfection and egg pasteurization. Some thermal technologies have been evaluated for the pasteurization of eggs. Microwave has limited penetration depth and is a technical challenge for egg pasteurization. However, radio frequency can penetrate eggshells effectively to inactivate Salmonella, considerably reduce processing time, and maintain the quality of the product. Nonthermal technologies such as ultraviolet, pulsed light, cold plasma, ozone, pressure carbon dioxide, electrolyzed water, and natural antimicrobials have been explored for surface cleaning of the intact egg as alternatives without affecting the internal quality. This review presents some of these novel technologies and the current challenges. It discusses the possible combination of factors to achieve the egg's internal pasteurization and the eggshell's disinfection without affecting the quality at a low cost for the consumer.     

Volatile Flavor Profile of Saskatchewan Grown Pulses as Affected by Different Thermal Processing Treatments

The objective of this study was to identify and quantify the volatile flavor composition of selected Saskatchewan grown pulses including navy beans, red kidney beans, green lentils, and yellow peas, and to determine the flavor changes induced by thermal processing. Flavor profile of roasted flours, ground roasted seeds, pre-cooked seeds, pre-cooked slurries, pre-cooked–freeze-dried, and pre-cooked–spray-dried flours was studied using headspace solid-phase microextraction gas chromatography/mass spectrometry. The highest total area count (p < 0.05) was found in navy bean and the lowest in red kidney bean. 3-Hexanol was the most abundant volatile flavor compound. Pre-cooking significantly reduced (p < 0.05) volatile compounds total area count by 61.75%, except for the red kidney bean and yellow pea, whereas roasting significantly increased (p < 0.05) total area count for navy bean and red kidney bean. Major differences observed in relative peak area for the same chemical family showed that volatile flavor compounds of pulses were significantly affected by type and processing conditions. Basic knowledge of the volatile profiles of pulses and the flavor changes occurred following different types of thermal processing, could ensure better quality control of raw materials and help product developers meet flavor-delivery challenges. The relevant information may also be of interest to relevant industries targeting specific pulse-based food product development.     

Mitochondrial DNA Fragmentation as a Molecular Tool to Monitor Thermal Processing of Plant‐Derived,Low‐Acid Foods,and Biomaterials

Cycle threshold (Ct) increase, quantifying plant‐derived DNA fragmentation, was evaluated for its utility as a time‐temperature integrator. This novel approach to monitoring thermal processing of fresh, plant‐based foods represents a paradigm shift. Instead of using quantitative polymerase chain reaction (qPCR) to detect pathogens, identify adulterants, or authenticate ingredients, this rapid technique was used to quantify the fragmentation of an intrinsic plant mitochondrial DNA (mtDNA) gene over time‐temperature treatments. Universal primers were developed which amplified a mitochondrial gene common to plants (atp1). These consensus primers produced a robust qPCR signal in 10 vegetables, 6 fruits, 3 types of nuts, and a biofuel precursor. Using sweet potato (Ipomoea batatas) puree as a model low‐acid product and simple linear regression, Ct value was highly correlated to time‐temperature treatment (R² = 0.87); the logarithmic reduction (log CFU/mL) of the spore‐forming Clostridium botulinum surrogate, Geobacillus stearothermophilus (R² = 0.87); and cumulative F‐value (min) in a canned retort process (R² = 0.88), all comparisons conducted at 121 °C. D₁₂₁ and z‐values were determined for G. stearothermophilus ATCC 7953 and were 2.71 min and 11.0 °C, respectively. D₁₂₁ and z‐values for a 174‐bp universal plant amplicon were 11.3 min and 9.17 °C, respectively, for mtDNA from sweet potato puree. We present these data as proof‐of‐concept for a molecular tool that can be used as a rapid, presumptive method for monitoring thermal processing in low‐acid plant products.     

SOFTENING KINETICS OF COOKED DRY BEANS AT TEMPERATURES BELOW 100C

New value‐added dry bean products, such as sugar‐coated beans, require a shorter cooking time (15–30 min) and lower temperature (under 100C) than typical canned beans. Michigan bean classes navy, great white northern, small white, small red, dark red kidney, light red kidney, vine cranberry, bush cranberry, pinto and black beans were cooked at constant water temperatures of 90, 95 and 99C for 5–120 min. Isothermal rate constants for texture were estimated at each temperature for each bean class based on a modified first‐order model and an n ^th ‐order model. Heat transfer coefficients were estimated using aluminum beans and lumped capacity analysis. Isothermal parameters (rate constant and activation energy) and a nonisothermal parameter (activation energy) were used to predict texture from dynamic‐temperature experiments. The first‐order model (isothermal) was accurate up to 30 min, but was not appropriate for time greater than 30 min. The n ^th ‐order was considered superior to the modified first‐order model, because only three rather than four parameters needed to be estimated for similar accuracy. The nonisothermal method can save experimental time compared with the isothermal method, because additional experiments at different constant temperatures are unnecessary. A nomograph of equivalent heating time versus constant heating temperature was shown as a useful tool for process design.