China
Africa
Explore chapters and articles related to this topic
Pullulan: Recent Progress and Technological Prospects
Published in Shakeel Ahmed, Aisverya Soundararajan, Pullulan, 2020
Pullulan, a polysaccharide polymer, is tasteless and odorless. It is impermeable to oxygen and is soluble in water; its membrane is employed for coating and is used as packaging materials for various food products and drugs [69]. It can also be applied in the form of partial substitute for starch in low-calorie food as it does not degrade through in vivo digestive enzymes such as amylase and pepsin. It is used as microencapsulating material for spices and flavors to be used as seasonings [70]. The oxygen-resistance ability of pullulan films helps protect the freely oxidized fats and vitamins in food substances. The films are used as coating or packaging substance in the foods that are dry, such as nuts, noodles, meats, vegetables, and confectionary items [71]. Pullulan does not get comprehended from bacteria and molds. So it is mixed with different food or non-food substances for influencing the shelf-life of any products to protect the contents from degradation, as shown in Table 2.1. Pullulan is added in the process of making cakes as it helps to retain shape, moisture, and even the look of the cake after preparation. In frozen foods, it helps in preventing the loss of water or drip, and it also tends to improve the yield of production in other food products as well.
Computerized Food Freezing/Chilling Operations
Published in Gauri S. Mittal, Computerized Control Systems in the Food Industry, 2018
Hosahalli S. Ramaswamy, Shyam S. Sablani
It is generally recognized that although freezing permits maximal retention of nutritional quality, and frozen food traditionally is thought by consumers to be the best alternative to fresh foods, freezing nevertheless results in irreversible texture changes from the damage caused by the formation of ice crystals. Hence quality-conscious consumers are seeking other processes to retain better sensory characteristics than possible with frozen foods. Chilling processes with a rapid distribution cycle, the cook–chill processes currently popular in catering circles, and refrigerated sous-vide processes are examples of such processes.
Food Freezing
Published in İbrahim Dinçer, Heat Transfer in Food Cooling Applications, 1997
The freezing process must always be fast enough to minimize the development of microbiological and enzymatic changes in the food product. In the past, the beneficial effect of very quick freezing on the quality of frozen foods has been overestimated within certain limits, meaning that the rate of freezing does not affect the quality of most frozen foods. This should not be interpreted to mean that the freezing rate has no effect on the quality of frozen foods, as most foods suffer from being frozen very slowly and limited foods demand ultraquick freezing. Fish and poultry products seem to be more vulnerable to very slow freezing than most other foods, and meat (e.g., beef, lamb) rather less. Strawberries and beans have better texture and water-holding ability if frozen ultraquickly, whereas fruits and vegetables with a higher starch content, e.g., peas, are not as sensitive to freezing speed. In commercial food freezing applications, the mean freezing rates range between 0.5×106m/s and 300×106 m/s, for example, 0.5×106 m/s, leading to slow freezing, for bulk freezing in blast rooms,1.5×106 to 10×106 m/s, leading to quick freezing, for retail packages in blast or plate freezers,15×106 to 30×106 m/s, leading to quicker freezing, for IQF of small products, especially in the fluidized bed freezer, and30×10−6 to 300×10−6 m/s, leading to ultraquick freezing by spraying with or immersion in liquid gases.
Effect of particle size and concentration on the chemical, physical and functional properties of rice-cornsilk composite flour paste
Published in Journal of Dispersion Science and Technology, 2022
Chalinee Tiwaree, Jirarat Anuntagool
Gel syneresis after a freeze-thaw cycle has been a critical problem in the frozen food industry, resulting in consumers' rejection of food products.[9] Various works have been carried out to tackle the problem.[9–11] The composite flour paste resisted syneresis better than RF paste, as shown in Figure 5. No significant difference (p ≥ 0.05) in syneresis percentage was found when adding 5% or 10% CS particles of any size. The addition of smaller-sized CS75 and CS45 significantly reduced the syneresis. CS45 addition reduced the syneresis of starch paste from 30% syneresis without CS to around 3% after the first freeze-thaw cycle and to around 10% after 5 freeze-thaw cycles. The ability of CS to reduce gel syneresis reported in this study is better than 2% cassava starch addition to 8% rice starch gel, which could reduce syneresis from 38.1% to 21.9% after the first freeze-thaw cycle and 57.5% to 45.4% after the fifth freeze-thaw cycle.[9] The ability to reduce freeze-thaw loss could be due to the high water-binding capacity and low solubility of the CS particles. It is worth noting that the ability of the cornsilk particles to prevent freeze-thaw loss could alter the syneresis resistance of the composite rice flour to be equivalent to a low amylose starch gel.[9,27,28] Lastly, gel strength did not correlate with the syneresis value (r = 0.440).
Intelligent control and energy efficiency analysis of the multi-functional freezing and refrigerated storage system
Published in International Journal of Green Energy, 2019
Songsong Zhao, Zhao Yang, Lei Zhang, Na Luo, Aiqiang Chen
It is known that the refrigerated storage or processing of frozen food is necessary after quick-freezing. When the hot-gas bypass valve was open, the evaporation temperature increased rapidly. At the moment, because the temperature of the evaporator was higher than that of the freezing chamber, the heat of the evaporator would be absorbed by the freezing chamber. The temperature of the freezing chamber would increase. It only took 10 min to make the temperature increase from −31.0°C to −18.0°C. Meanwhile, as a result of the opening of the hot-gas bypass, the discharge pressure of the compressor decreased quickly, which caused the sudden decrease of the discharge temperature (Byun, Lee, and Jeon 2008). With an intelligent control of the hot-gas bypass valve, the temperature of refrigerated storage for frozen food was relatively stable. The temperature fluctuation was lower than 0.4°C. In terms of the discharge temperature, it was higher than 60°C during the quick-freezing process. However, the intelligent control of the hot-gas bypass made the discharge temperature decrease between 50°C and 55°C obviously. As shown in Figure 7, during the hot-gas bypass control, the compressor power decreased and the evaporation temperature increased, which caused an improvement of the COP of the system (Cho, Kim, and Jang 2005; Wang, Liu, and Shi 2016). The energy consumption could be saved about 9.7%. Furthermore, the service life of the compressor will be longer because of the continuous and stable operation of the system.
Modelling and solving the split-delivery vehicle routing problem, considering loading constraints and spoilage of commodities
Published in International Journal of Systems Science: Operations & Logistics, 2023
Sherif A. Fahmy, Mohamed L. Gaafar
Distribution of perishable products requires accounting for the quality, freshness, transportation modes, loading and packing arrangement, among others. Considering all or some of such constraints increases the complexity of the VRP or SDVRP, but provides more realistic solutions for the addressed problems. A review of VRP applications in the perishable products industry can be found in Akkerman et al. (2010) and Utama et al. (2020). Examples include the work proposed in Amorim & Almada-Lobo (2014), where the VRPTW for perishable products was formulated as a multi-objective model, reflecting a trade-off between the distribution costs and the average freshness of all products at delivery. Freshness at delivery was expressed as the remaining shelf-life of the product, given a 100% freshness level at the pickup point. A single depot with a homogeneous fleet of vehicles was considered, and it was assumed that all products are of equal size but with different shelf lives. The model was solved for small instances using the -constraint method and for larger instances using a hybrid approach that utilised a non-dominated sorting GA (NSGA-II) and a linear solver. In Zhang & Chen (2014), a single objective optimisation model to solve the VRP in the frozen food industry was proposed, also considering a single depot, multiple customers, homogeneous vehicles and multiple products. In addition, the study accounted for different unit volumes for the different products. The objective was to minimise total cost including transportation, refrigeration, penalty and cargo damage costs. The delivery of products outside customer time windows was allowed but with a penalty cost. Refrigeration costs considered temperature differences during transportation and during loading and unloading. A GA was proposed to solve the problem.