Blast Freezing Research Articles

Examination of Thermal Dispersion and Airflow within a Refrigerator

A blast freezer, characterized by its capability to diminish the core temperature of cooked food from 100 °C to -18 °C within 270 minutes, constitutes a critical component in this preservation process. This study endeavors to model a blast freezer system employing Computational Fluid Dynamics (CFD) methodologies, subsequently validating the CFD analysis through empirical investigations. The pressure-based k-ε turbulence model is employed to solve the Navier-Stokes and energy equations. The ensuing analyses encompass airflow assessments and temperature evaluations for unloaded and fully loaded blast freezers. Results gleaned from experiments and analyses indicate a temperature escalation within the cabin as it approaches the enclosure walls. Maximum velocities of 31.1 m/s and 26.9 m/s are recorded for unloaded and fully loaded freezers. The average disparity between the CFD and experimental models is computed as -0.7 °C, signifying a close alignment between the simulated and actual outcomes.

Double Freezing Beef Strip Loin Steaks at Blast or Consumer Freezing Temperatures in Vacuum and Overwrapped Packaging

Our objective was to evaluate the combined effect of blast freezing vacuum packaged USDA Low Choice Longissimus lumborum beef steaks followed by consumer freezing of retail overwrapped steaks upon objective and subjective measures of beef palatability. The experimental design utilized a randomized complete block with a 3 × 3 treatment structure of targeted freezing treatments initially in vacuum and secondly in overwrap packaging (unfrozen = NOT; blast frozen at −34.4°C = BF; consumer-frozen at −17.8°C = CF) to accomplish 9 treatment combinations. Descriptive sensory attributes were evaluated by trained panelists on a 100-point line scale. Slice shear force and expressible moisture were assessed. Data were analyzed via PROC GLIMMIX using a randomized complete block design with a 3 × 3 treatment structure. Of descriptive panel attributes, overall juiciness was the only interaction observed (P = 0.006). Though similar to steaks initially CF in the vacuum package and followed by a second freeze (CF/BF or CF/CF) in the overwrap package, steaks singly frozen to simulate a CF (CF/NOT and NOT/CF) resulted in the overall driest ratings by panelists (P = 0.006). Only bloody/serumy differed (P = 0.002) within the initial freeze, where steaks not frozen (NOT) in the vacuum package were rated higher than those that were frozen (BF or CF). During the second freeze in the overwrap package after retail display, steaks BF rated higher for oxidized (P = 0.051) off-flavor than steaks CF and higher than both CF and NOT steaks for refrigerator-stale (P = 0.006) off-flavor; all other attributes did not differ (P ≥ 0.155). Although some freezing combinations that included CF were generally lower for overall juiciness, BF vacuum packaged steaks had no effect on palatability when compared to NOT steaks. The beef industry and consumers should feel confident using freezing as a means to extend shelf-life of beef steaks.

Thermomechanical effects during air blast freezing of fruit pulp model solutions with different sucrose concentrations in metal drums

The strains on the metal drums surfaces caused by the ice volumetric expansion during the freezing of model solutions of fruit pulps were evaluated by extensometers. 200 kg of model solutions of 0.5% k-carrageenan (w/v) added 0.5%, 10% or 20% (w/v) sucrose into metal drums were frozen in air blast freezer at −25 °C. Strain gauge sensors were installed on the side surface and bottom of the drums in a balanced Wheatstone bridge circuit. The resulting stresses and temperature profiles inside the packages were measured simultaneously. The non-uniform temperature distribution in the product was proven by IR thermography. There was reduction in the freezing temperature and stresses in the packages with the increase in the sucrose concentration. The restricted surfaces, preventing the expansion of the ice, yielded great stresses in the frozen solutions and induced cracking in the free surfaces of the solutions, especially in the systems with lower concentrations.

Optimizing airflow in spiral blast freezers

Spiral blast freezing is a common unit operation used in food processing facilities for rapidly freezing a variety of foodstuffs. The purpose of a blast freezer is to generate high velocity, low temperature air flow over food products being conveyed within refrigerated enclosures to accomplish the freezing process. However, air flow patterns observed within field operating blast freezers are often suboptimal, resulting in diminished system performance. This paper applies a Monte Carlo simulation technique to a food product freezing simulation in order to identify velocity profiles that optimize the freezing process. A one-dimensional food product model is used to evaluate the interplay between the time variation in the magnitude of the air velocity over food products conveyed through the freezing system and the resulting dwell time needed to achieve a target product core temperature at the blast freezer exit. Temporal heat transfer coefficients derived from field measurements made in a newly installed spiral blast freezer serve as a basis to calibrate the one-dimensional product model.The results of the Monte Carlo analysis show freezing system performance is improved when high and stable air velocities over the product are achieved early in the freezing process dwell time. Air flow patterns within a freezing system that result in high air velocity later in the freezing process dwell time are suboptimal. Field-measured data on a newly installed spiral blast freezer showed this suboptimal air flow pattern and the use of baffling within the spiral enables improved airflow leading to an estimated 10 % increase in production throughput.

Thermoeconomic model for diagnostic techniques to evaluated vapor compression refrigeration system performance

In recent years, it has been possible to observe a significant expansion of the refrigeration and air conditioning industry. Considering that food refrigeration systems (blast chilling or freezing, cold storage, retail display, etc.) and air conditioners are large energy consumers, this work presents a methodology for evaluating the performance and behaviour of these systems using the thermoeconomic diagnosis concept. The thermoeconomic model used allowed the definition of the condenser and expansion device products, which is not trivial for these components. With that, the thermoeconomic diagnosis was used to evaluate the degradation of refrigeration system components, together with the influence of individual component degradations on efficiency, cooling capacity, operating parameters, and power consumption of the whole system. Through this analysis, a prognosis of system behaviour was obtained, which can be used for maintenance scheduling, as well as for the comprehensive energetic and exergetic analysis of a refrigeration system and each of its components.

Cryoprotective role of vacuum infused inulin on the quality of artichoke: Interactive effects of freezing, thawing and storage period

Freezing of artichoke is a promising alternative to storing it in brine and canning. The perishable vegetable was vacuum infused with inulin to improve freezing tolerance. Artichokes with and without inulin were frozen by static, air blast and individual quick freezing (IQF) methods and thawed by microwave, 25 °C and 4 °C temperature levels at each month of 6-months storage. Process conditions were evaluated by multivariate analysis of variance (MANOVA) and were found significant on the quality parameters. Inulin infusion better conserved the aw, color, texture, ascorbic acid and overall integrity of artichokes during frozen storage. Inulin incorporation and IQF showed mutual positive effect on drip loss. Polyphenol oxidase (PPO) activity values fitted to 2nd order kinetic and the highest residuals were determined in static freezing. PPO showed alleviating effect on total phenolic content. Vacuum impregnation caused a color difference prior to freezing, but was found effective for maintaining color during storage. As a result, the use of quick freezing techniques together with the addition of cryoprotectant was effective in the preservation of artichoke quality attributes during frozen storage.

Quality and microstructure of tilapia fillets (Oreochromis niloticus) subjected to different freezing methods

The Nile tilapia (Oreochromis niloticus) fillets were frozen with static air (SA) at -20 °C, air blast freezing (AF) at -25 °C, combined method (CM - immersion in liquid nitrogen followed by AF) and cryogenic freezing (CF - immersion in liquid nitrogen). The effects of different freezing methods and of storage time at -18 °C (0, 30, 60 and 90 days) on fillet quality were evaluated. The temperature records were obtained, and the freezing times were determined by monitoring the temperatures of the geometric centers of the fillets. For CF, CM, AF and SA, the freezing times were 5.32, 127, 146 and 268 min, respectively. The quality of the frozen fillets was evaluated by measuring pH, volatile nitrogenous bases (TBV-N), thiobarbituric acid reactive substances (TBARS), and fatty acids and by obtaining a texture profile and performing scanning electron microscopy (SEM). The samples frozen by CF, after storage, had the highest levels of TBV-N because the high freezing rate produced superficial cracks that negatively affected the quality of the fillets. Freezing the samples with SA produced the worst quality indices and the microstructure was visibly damaged, with greater spaces between the fibers left by ice crystals. For all parameters evaluated, freezing with AF and CM resulted in fast freezing rates and better-quality tilapia fillets for 90 days of storage.

Effects of different freezing methods on muscle qualities and myofibrillar protein properties of red drum (Sciaenops ocellatus) during storage

The freezing of aquatic products without causing significant changes in quality is recently attracting much attention. In this study, the effects of air freezing (AF, -20 °C), blast freezing (BF, -35 °C), liquid nitrogen freezing (LNF), and immersion freezing (IF, -35 °C) by 20 % ethanol, 20 % propylene glycol, 10 % glycerol, and 10 % sodium chloride aqueous solutions, respectively, on muscle qualities and myofibrillar protein properties of the red drum were investigated. The results indicated that the freezing rate of IF was 2.66 cm/h, which was 6.33 times higher than that in AF groups. Compared with AF and BF, the ice crystals were smaller and more uniformly shaped, with properties of lower water migration and less texture softening after cryogenic liquid freezing of IF and LNF group aquatic products. Immersion freezing showed the same superiority in maintaining the freshness of fish fillets and retaining the protein structure as liquid nitrogen storage. Overall, IF has similar effects to LNF in maintaining muscle qualities and myofibrillar protein properties. This study describes a new freezing method that uses 20 % ethanol, 20 % propylene glycol, 10 % glycerol, and 10 % sodium chloride aqueous solutions as immersion freezing medium. The multi-compound freezing medium has the potential to be used for the freezing of aquatic products.

IMPLEMENTATION OF COLD CHAIN SYSTEM IN PEELED DEVEINED TAIL-ON VANNAMEI SHRIMP (Litopenaeus vannamei) PRODUCTS

Vannamei (Litopenaeus vannamei) Peeled Deveined Tail-On (PDTO) shrimp is frozen shrimp product consumers highly preferred. However, shrimp products are easily perishable that require a proper cold chain system to preserve their quality, shelf life, and nutritional value. This study investigated the cold chain implementation of PDTO shrimp processing in the fishery industry. The temperature of shrimp products, water, and rooms was monitored during processing. Results showed that the shrimp temperature measured in each process was below 5°C. However, abusive temperatures were detected in water used in the peeling and deveining step and soaking process, while water and shrimp temperatures altered each other. Moreover, room temperatures were recorded under 20°C, conforming to Ministry of Marine and Fisheries regulations. Air Blast Freezer and cold storage temperatures revealed that ABF and CS could not meet the company’s temperature standards. These findings may help shrimp companies monitor steps indicating to have temperature abuse attentively.

Design and analysis of a 20-feet modular cold storage system

Cold storage plays an essential role in the cold supply chain, especially for fishery products. Compact cold storage systems that can be easily moved across various locations are attractive for archipelagic regions. This study aims to design and analyze a 20-ft modular cold storage system. The design stages include the development of a geometrical model, calculation of cooling load, and selection of a refrigeration machine. The analysis of the designed cold storage system was performed using transient computational fluid dynamic simulations using Ansys Fluent. The compact 20-ft cold storage design consists of three main rooms: the anteroom, air blast freezer room, and freezer storage room. The calculation results showed a maximum cooling load of about 6.6 kW occurring in the air blast freezer room at noon. According to the temperature distribution from the transient computational fluid dynamic simulation, each room had different cooling characteristics, with the highest cooling rate of 94.59 W/h in the air blast freezer room, achieving a targeted temperature of −40 °C in 5 h.

Design of Air Blast Freezing System Using Cascade Refrigeration R290/R32 System with Capacity 5kg

Indonesia is a maritime country that has an abundance of marine catches. In 2022, the production of marine catches reached 24.85 millions tons, while the export amount was 1.221 millions tons. This is due to the limited technology that can extend the freshness of marine catches. Based on this problem, a cooling system was designed in the form of an ABF that can freeze marine catch products. The Air Blast Freezing (ABF) system is designed at an air temperature of -40oC using a cascade refrigeration system. The working fluid used is R290/R32 hydrocarbon, which has very low GWP and ODP so it is safe for the environment and the earth's ozone layer. The results obtained show that the cooling load is 444.037 Watts, the LTC compressor power and HTC compressor power are 116.19 Watts and 205.98 watts. The designed air blast freezing system has a surface area of LTC evaporator of 2.670 m2 and HTC condenser of 4.780 m2. The calculated capillary pipe length is 1.94 m for HTC and 1.51 m for LTC, the COP of the ABF system is 2.774.

Effect of air blast freezing and frozen storage on inactivation of Vibrio vulnificus in Pacific oysters (Crassostrea gigas)

Air-blast freezing followed by frozen storage at different temperatures was assessed for inactivation of Vibrio vulnificus in Pacific oysters (Crassostrea gigas). Pacific oysters were allowed to bioaccumulate a cocktail of six strains of V. vulnificus. They were then air-blast frozen at −55 °C followed by frozen storage at −8 °C, −13 °C, −18 °C, −23 °C and −28 °C. V. vulnificus reductions were enumerated at different sampling times from 0 to 360 days. Air-blast freezing and frozen storage inactivated V. vulnificus in Pacific oysters in a two-phase inactivation pattern, with rapid inactivation during the first 3 days after air-blast freezing (short-term effect) followed by slower log-linear declines during frozen storage (long-term effect). The effects of storage temperature on V. vulnificus inactivation (log10 MPN/day) were assessed using a combined model that includes effects from both short- and long-term storage. The US National Shellfish Sanitation Program requires that postharvest processes to reduce Vibrio concentrations achieve ≥3.52 log reductions. At −18 °C this was achieved after an average of 90 days, but 95% confidence was not achieved until 123 days. Lower frozen storage temperatures caused slower declines of V. vulnificus. As well as artificially bioaccumulated V. vulnificus, we modeled inactivation of naturally occurring V. parahaemolyticus and showed that the results of a previous North American study fitted with our data. Their validated treatment for this organism in half-shell oysters can therefore be applied to New Zealand whole-shell oysters. This study will help guide oyster producers/processors aiming to achieve significant inactivation of Vibrio bacteria in their product, by providing a starting point for developing suitable frozen storage time/temperature conditions for Vibrio inactivation.

Study on various hot-gas defrosting configurations for CO2-NH3 cascade deep freezer

Four hot-gas bypass defrosting configurations for CO2-NH3 cascade blast freezer for application in fish processing firm are numerically investigated. Due to the high moisture content of fish, defrosting is necessary after every 4 to 5 h of batch operation. A thermodynamic model for the cascade system and defrosting was developed to study various defrosting configurations formulated by rearranging the existing compressor to operate as a defrosting compressor and with the addition of an external defrosting compressor. From the simulation findings, it can be summarized that the conventional hot-gas bypass defrosting without defrost compressor is suitable for a high-capacity cascade refrigeration system with more than three evaporators. For low cooling capacity refrigeration systems, a defrosting compressor is necessary to elevate the temperature above the cascade condensing temperature. A dedicated defrosting compressor with a power consumption of 3.1 kW and a modified refrigeration/defrosting compressor with a power consumption of 6.8 kW can deliver 33.3 kW of heating at a temperature of +10 °C (45 bar). Incorporating a desuperheater between the main and defrosting compressors reduces compressor temperature and maintains the lubricating oil stability, without change in defrosting energy consumption and less exergy loss. The defrosting efficiency is obtained in the range of 39.7–42% which is in agreement with published literature.

Effect of Liquid Nitrogen Freezing Temperature on the Muscle Quality of Litopenaeus vannamei.

The implications of different liquid nitrogen freezing (LNF) temperatures (-35 °C, -65 °C, -95 °C, and -125 °C) on the ice crystal and muscle quality of white shrimp (Litopenaeus vannamei) were investigated in this essay. The results showed that better muscle quality was maintained after LNF treatment compared to that after air blast freezing (AF) treatment. As the freezing temperature of liquid nitrogen decrease, the freezing speed accelerated, with the freezing speed of LNF at -125 °C being the fastest. However, an excessively fast freezing speed was not conducive to maintaining the quality of shrimp. Among all the freezing treatments, LNF at -95 °C led to the lowest thawing losses and cooking losses, and the highest L* values, indicating that LNF at -95 °C could keep the water holding capacity of frozen shrimp better than that with other freezing methods. At the same time, LNF at -95 °C resulted in higher water holding capacity, and hardness values for shrimps than those with other frozen treatments (p < 0.05). In addition, the results of the water distribution of shrimps showed that treatment with a -95 °C LNF reduced the migration rate of bound and free water. Meanwhile, the microstructural pores of shrimps in the -95 °C LNF group were smaller, indicating that the ice crystals generated during -95 °C LNF were relatively smaller than those generated via other frozen treatments. In conclusion, an appropriate LNF temperature (-95 °C) was beneficial for improving the quality of frozen shrimp, and avoiding freezing breakage.

Defrosting and Blast Freezing Dark Matter

Defrosting and Blast Freezing Dark Matter

Volatile aroma and physicochemical characteristics of freeze-dried coconut water using different encapsulating agents

This research studied how different types and concentrations of encapsulating agents impacted freeze-dried coconut water products. Volatile aroma and physicochemical product characteristics were evaluated. The encapsulating agents were maltodextrin 4–8% (w/v), polydextrose 4–8% (w/v) and xanthan gum 0.1–0.3% (w/v). A plate freezer and an air blast freezer were used to pre-freeze the coconut water before drying. Freezing time had no impact on moisture content and water activity. The flavor compounds of coconut water is composed of alkanes, aldehyde, ketones, organic acids and some other flavor substances. Encapsulating agents are the main factors affecting the flavor of coconut water. Optimal conditions for producing dried coconut water were adding polydextrose at a concentration of 8%. Volatile compounds were assessed under different conditions of SPME- GC-TOFMS. The composition of flavor compounds in coconut water is complex and mainly includes esters, aldehydes, and phenols. Results showed that encapsulating agents improved the volatile aroma of dried coconut water products.

Recent developments in freezing of fruits and vegetables: Striving for controlled ice nucleation and crystallization with enhanced freezing rates.

Fruits and vegetables are rich in essential nutrients such as minerals, vitamins, and antioxidants; however, they have short shelf life. Freezing is a superior method of preservation compared to other techniques with respect to nutrient retention and maintenance of sensory attributes. However, several physical and textural quality changes associated with freezing and thawing pose a serious problem to the quality of frozen products. Some of the disadvantages associated with the currently employed methods for freezing fruits and vegetables include low rates of heat exchange in blast freezers, shape limitation in plate freezers, high cost of operation in cryogenic freezing, and freezing solution dilution in immersion freezing. Therefore, novel freezing technologies have been developed to achieve controlled ice nucleation and crystallization, enhanced freezing rate, decreased phase transition time, and maintained temperature stability. This review discusses some of the most recent approaches employed in freezing and points to their adoption for maintaining the quality of fruits and vegetables with extended storage.

Pengaruh Teknik Pembekuan Ikan Tongkol (Euthynnus affinis) Terhadap Organoleptik di PT. Aceh Lampulo Jaya Bahari

Tuna contains high protein so that it fulfills the nutritional needs of the human body. Tuna is a marine fish that contains omega 3, vitamins, protein and minerals. This study aims to determine the effect of the freezing technique of tuna (Euthynnus affinis) on organoleptic at PT.Aceh Lampulo Jaya Bahari using a temperature of -30oC to -40oC with a freezing time of about 8 - 12 hours. Methods This study used a qualitative method consisting of research on the first with the influence of the technique of freezing tuna (Euthynnus affinis) with a comparison of 3 freezing methods, the second stage carried out an organoleptic analysis (ice layer, dehydration, discoloration, appearance, smell, texture.) on frozen tuna. The results of the value of the ice layer showed that the most preferred value by the analyst was the value of the semi contact plate freezer 7 ± 0.67 and cold storage 7 ± 0.67, the dehydration indicated the value most preferred by the analyst was the value of the semi contact plate freezer 7 ± 0.67 and cold storage 7 ± 0.67. The result of the value of dehydration shows the value most preferred by the analyst is the value of the semi contact plate freezer 7 ± 0.78. The result of the value of the appearance shows the value most preferred by the analyst is the value of air blast freezer 7 ± 0.50. the result of the value of the appearance shows the most preferred value by the analyst is the value of the air blast freezer 7 ± 0.50, the result of the value of the odor shows the most preferred value by the analyst is the value of the semi contact plate freezer 7 ± 0.41 and cold storage 7 ± 0.41, the value of the texture shows the most preferred value by the analyst is the value of air blast freezer 7 ± 0.25, semi contact plate freezer 7 ± 0.25 and cold storage 7 ± 0.25.

Tingkat Kandungan Histamin pada Ikan Cakalang (Katsuwonus Pelamis) dengan Metode Pembekuan yang Berbeda di CV. Novira Abadi Kota Banda Aceh

The fisheries sector in Indonesia has a greater potential, namely pelagic and demersal fish populations including skipjack tuna and tuna skipjack tuna are referred to as commodities that have high nutritional value but are easily damaged because they contain lots of protein which is high in free amino acids for microbial metabolism. production of ammonia, biogenic amines, organic acids, ketones and sulfur composition. Fish is one of the food products that is prone to deterioration in quality due to the action of enzymes or microbial growth. Handling of fresh fish can be done by applying cold temperatures through freezing techniques to prevent deterioration of fish quality. The SCF (semi contact plate freezer) method is a product freezing process between refrigerated shelves and this process takes place quickly. The use of semicontec in this product is fish arranged in a pan, which consists of 144 pans of cold air around the product with a temperature of - 40°C for 5 hours, with a temperature of 17.4°C in skipjack tuna, the histamine content was 0.3 ppm. ABF (Air Blast Freezer) freezing method. Freezing is done by placing the fish products that have been arranged in a pan and putting them into the ABF (air blast freezer) at the temperature used in the company, which is -35°C for 22 hours. in the arrangement of the fish that is included in the air blast freezer Freezing air blast freezer, which is a cold media made from freon that is used to freeze or ripen fish. The temperature of the fish after being frozen at air blast freezer 15.400C. by producing histamine levels in skipjack tuna 3.9 ppm, where the fish can still be consumed.

Performance analysis of a CO2/NH3 cascade refrigeration system with subcooling for low temperature freezing applications

CO2/NH3 cascade refrigeration system is an all-natural refrigeration option which can be specifically designed and gainfully operated for low temperature applications in warm ambient conditions. In the present study, a novel CO2/NH3 cascade refrigeration system with subcooling is proposed and evaluated as an alternative to the HFC-404A refrigeration system, which is typically used for blast freezer applications in the seafood processing industry. The performance of the proposed system is also compared with a conventional CO2/NH3 cascade refrigeration system without any subcooling arrangement. Real compressor specific equations were used to simulate the performance of the systems under various conditions. The proposed system yields 26% higher performance ratio (COP) than the conventional HFC-404A system at the design condition. In addition, the proposed subcooling arrangement enhances COP of the conventional CO2/NH3 cascade unit by around 5%. The system performance is investigated theoretically under various condensing temperatures and subcooling degrees. The annual energy demand and total equivalent warming impact (TEWI) of the proposed system are 15% and 48% lower than for the conventional HFC-404A system which results in significant economic and environmental benefits. Overall, the proposed system exhibits superior energy efficiency and offers a climate and environmental friendly alternative to the conventional environmentally harmful systems within the seafood industry. Adoption of such energy efficient all natural and clean refrigerant technology is crucial for the future phase out of hydrofluorocarbon (HFC) fluids, as ratified in accordance with the Kigali Amendment to the Montreal Protocol in India and other tropical countries.