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.     

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.     

Inverse Superposition for Calculating Food Product Temperatures during In-container Thermal Processing

A procedure was developed for theoretical calculation of internal product temperatures during in-container sterilization of foods. Experimental product temperatures were determined through traditional heat penetration tests (processing in a retort with come-up time of increasing temperature and holding time at constant temperature). These were used to produce, through a proposed inverse superposition solution, a “standardized,” normalized, dimensionless product temperature curve corresponding to the response of product temperature to a constant retort temperature profile. This “standardized” curve was then used, through Duhamel's superposition theorem, to calculate product temperatures for time-varying retort temperature profiles. Limitations associated with the application of Duhamel's theorem were also transferred to the proposed methodology. Theoretical, for perfect mixing, and experimental, for conduction heating, data were used in example calculations.     

Kinetic Parameter Estimation for Quality Change during Continuous Thermal Processing of Grapefruit Juice

Reaction order, activation energy (E_a) and average rate constant (k_av) were evaluated by dynamic modeling for color degradation of grapefruit juice during thermal processing. Simulated aseptic conditions were: 85–135°C, 40–175 set processing time, and average velocities 5–30 cm/set. Quality was assessed by nonenzymatic browning index (NEBI) and S-hydroxymethyl-furfural (HMF). Average values for reaction-order and energy of activation were: 0 and 21.4 kcal/g-mol (NEBI) and 0.3 and 23.2 kcal/g-mol (HMF), respectively. These values were compared with those contained in the deformed ellipsoid which define the 90% joint confidence interval of all possible parameter combinations. Based on initial and final concentrations, the method can predict effects of processing on liquid foods.     

Modified Spore Inoculation Method for Thermal-Process Verification of Pinto Beans and Green Beans Canned in Two Large Reusable Containers

As an alternative to standard metal cans, 2 large, reusable containers with volumetric capacities 3.6 to 3.8 times larger than a standard #10 can were constructed of nickel‐plated steel. Process times and cold point determinations were previously determined using mathematical approximations of heat‐penetration data. It was necessary to verify the adequacy of these process times using inoculated containers. Because it was impractical to use traditional inoculated can procedures, a modification was developed using spores of Clostridium sporogenes PA3679 immobilized in alginate beads contained in brass tubes. Adequacy of the calculated thermal processes was demonstrated; no viable anaerobic spores survived in the inoculated packs.     

Green Pea and Garlic Puree Model Food Development for Thermal Pasteurization Process Quality Evaluation

Development and selection of model foods is a critical part of microwave thermal process development, simulation validation, and optimization. Previously developed model foods for pasteurization process evaluation utilized Maillard reaction products as the time–temperature integrators, which resulted in similar temperature sensitivity among the models. The aim of this research was to develop additional model foods based on different time–temperature integrators, determine their dielectric properties and color change kinetics, and validate the optimal model food in hot water and microwave‐assisted pasteurization processes. Color, quantified using a^* value, was selected as the time–temperature indicator for green pea and garlic puree model foods. Results showed 915 MHz microwaves had a greater penetration depth into the green pea model food than the garlic. a^* value reaction rates for the green pea model were approximately 4 times slower than in the garlic model food; slower reaction rates were preferred for the application of model food in this study, that is quality evaluation for a target process of 90 °C for 10 min at the cold spot. Pasteurization validation used the green pea model food and results showed that there were quantifiable differences between the color of the unheated control, hot water pasteurization, and microwave‐assisted thermal pasteurization system. Both model foods developed in this research could be utilized for quality assessment and optimization of various thermal pasteurization processes.     

Nutritive Quality of Long-Distance Shipped Green Beans for Processing

Vitamin A and C contents of bulk raw snap beans for canning from distant sources (up to 12 hr) were measured and compared to that from local sources. Statistically significant differences were found between vitamin contents of beans arriving from some locations for some seasons, but equally large season-to-season variations were also found. Much of this variation could be attributed to cultural conditions. Differences found were relatively minor, particularly in view of the large losses which are known to occur during processing. Our observations indicate that retention of these two vitamins following long distance shipping is at least as great as retention of other quality factors.     

A Theoretical Study for Determination of Quality Equivalent Points for Volume Average Quality Evaluation in Conduction Heating Canned Foods

ABSTRACT:  In the present study, a set of quality equivalent points, that is, points where the retention of a particular quality attribute at the end of a thermal process is equal to the volume average quality retention, was determined for conduction heating products in cylindrical containers. For this, initially, the temperature distribution inside the product during the thermal process was numerically calculated, assuming uniform initial product temperature, constant heating and cooling medium temperatures, and infinite heat transfer coefficient between the cylinder walls and the heating or cooling medium. Next, remaining concentration data at the end of the process were obtained at various points within the container for a heat labile quality factor following 1st-order degradation kinetics. Thereafter, the volume average remaining concentration for the quality parameter under consideration was calculated and the quality equivalent points were identified. The influence of product, quality factor, and process characteristics on the location of the quality equivalent points, was examined. For every case investigated, the entirety of quality equivalent points was modeled by the use of a single parameter, the empirical j value. For most cases of common practice, a j value between 0.34 and 0.40 was found appropriate for volume average quality retention calculations. Thus, by collecting temperature data during processing at a quality equivalent point, product quality at the end of the process can be assessed.     

小龙虾加工和流通过程中的食品安全与品质控制技术研究进展

小龙虾的加工和贮运流通是小龙虾全产业链中的重要环节之一,小龙虾质量安全与品质控制关系到百姓食品安全保障、风味和营养需求以及企业经济效益等,需要重点关注.本文根据原料及加工工艺、风味、贮运、消费要求及售卖产品特点不同,重点对小龙虾生鲜产品、半成品冻品、成品冻品和即食小龙虾在加工和流通过程中的食品安全与品质控制技术研究现状...     

即食梅香黄鱼热杀菌过程中的品质变化

为研究软包装即食梅香黄鱼在热杀菌过程中的品质变化,比较不同杀菌温度时间组合、不同喷淋水升降温速率在一定温度下杀死90%的微生物所需要的时间(F值)、热加工过程中导致食品外观特性变化的热损失值(C值)和品质指标(色泽、质构、汁液流失率)。结果表明：杀菌时间越长,F值增加越明显;杀菌温度越高,增加单位时间所带来的F值、C值的增加越明显;喷淋水升降温速率快慢相比,在达到相同F值时,所需的杀菌恒温时间是前者大于后者,前者表面C值更大,两者中心C值接近,前者C/F值也更大;高温短时杀菌色泽、质构好、汁液流失率少;喷淋水升降温速率快,汁液流失率少。在实验范围内适宜的杀菌条件为：127℃、升温速率fh＝10.99min,降温速率fc ＝12.32min。     

客家炒青绿茶加工过程中品质成分的动态变化

为了研究客家炒青绿茶加工过程中的主要品质成分动态变化规律，以广东客家小叶群体种-仙湖茶为原料，按摊青、杀青、揉捻、炒青、辉干等工艺制作炒青绿茶，对加工过程中的主要内含物成分及香气组成进行测定分析。结果显示，随着加工的进程，茶叶在制品含水率呈下降趋势，以“炒青”工序最为显著，含水率降至4.74%，降幅达91.63%；在“炒青”工序，茶叶生化成分含量变化最大：可溶性糖含量达到最大值5.71%，水浸出物含量达到最小值35.85%，氨基酸含量达到最小值2.71%。加工过程中，水浸出物、氨基酸、茶多酚及咖啡碱呈下降趋势，儿茶素总量及酯型儿茶素含量的变化趋势与茶多酚一致。香气组分以醇类物质为主，其中香叶醇、芳樟醇、二十八烷醇及叶绿醇等化合物在炒青绿茶不同阶段加工过程中占比较高且变化幅度较大。该研究揭示了客家炒青绿茶加工过程中的主要风味物质变化过程，可为优化客家炒青绿茶加工工艺与品质良好风味的形成提供数据参考。     

Temperature Prediction during Thermal Processing of Surimi Seafood

ABSTRACT: An interactive temperature prediction for surimi seafood was constructed and validated. The prediction model showed good agreement with experimental temperature profiles. The heat transfer coefficient (h) decreased with an increase of temperature difference (δT) between the sample surface and the water bath. The h had an effect on the convective heat transfer, resulting in a slower overall heat transfer at the beginning of heating. Thermal diffusivity (α) of surimi seafood was determined from experimental temperature profiles. The α increased slightly as the temperature difference (δT) between sample and water bath increased. The low a observed at small δT reduced conduction, resulting in a slower overall heat transfer.     

盐析菜罐头生产工艺研究

研究了盐析菜罐头的生产工艺,对盐析菜加工中灭酶、护色及杀菌技术进行了深入探讨。试验结果表明,100℃、60s的烫漂条件,400ppm氯化锌加200ppm亚硫酸钠护色效果最佳;灌汁液排气后封罐,在105℃、15min条件下杀菌,产品质量较好。     

缩短咸蛋加工时间及改善咸蛋品质的研究

探讨了缩短咸蛋加工时间及控制咸蛋在保存过程中咸度过度加重的方法。结果显示:不同的酸、碱添加剂对缩短咸蛋加工时间有不同的影响,并通过采用二段式加工工艺使咸蛋品质得到很大提高。     

Effect of Delayed Processing on Changes in Histamine and Other Quality Characteristics of 3 Commercially Canned Fishes

ABSTRACT: Changes in histamine and other quality characteristics were examined in 3 commercially important fishes, tuna ( Katsuwonus pelamis ), seerfish ( Scomberomorus commersonii ), and sardines ( Sardinella gibbosa ) through the canning process, at 3 different stages (raw, precooked, and canned) immediately on receipt and also after a delay of 6 h at ambient temperature (30 ± 2 °C). Tuna and seerfish remained sensorially acceptable when processed after delay, whereas sardines exhibited slight ammoniacal/putrid odor. TMA-N and TVB-N contents were low in precooked fish compared with their fresh counterparts, whereas in canned fish, both compounds increased significantly ( P < 0.05). Histamine content in the fish held for 6 h increased to 14, 17, and 8 ppm in tuna, seerfish and sardine, respectively, and never exceeded the maximum permissible limit of 50 ppm prescribed by the U.S. Food and Drug Administration. In precooked and canned fish, histamine was lower than in their raw counterparts and found to be within the range of 1.6 to 8.0 ppm in precooked and 1.2 to 4.3 ppm in canned fish. Holding the fishes destined for canning at 30 ± 2 °C for 6 h, therefore, was found to be safe from histamine toxicity problems.     

罐头食品热力杀菌过程节能减排工艺的研究

节能减排是我国基本国策,也是企业降低生产成本的需要。罐头食品杀菌过程中需要消耗较多的蒸汽和水,该课题利用罐头生产企业原有设备,以最少的投入,研究减少杀菌过程蒸汽量和用水量的新工艺,以降低罐头生产的单位能耗。     

Influence of the Thermal Stabilization Process on the Volatile Profile of Canned Tomato‐Based Food

The literature contains several papers dealing with the volatile constituents contributing to the aroma of fresh and processed tomatoes. Along with the traditional tomato‐based products, tomato‐based pâtés, characterized by complex ingredient formulations, are commonly consumed as a seasoning for pasta, and as a dressing for meats, salads, and sandwiches. To the best of our knowledge, no investigations have been published on the influence of thermal stabilization treatments on the composition of volatile compounds in tomato‐based pâtés. To this aim, thermally stabilized and not stabilized tomato‐based pâtés were subjected to the analysis of volatile compounds. The results obtained highlighted the influence of the thermal stabilization process on the evolution of volatile composition tomato‐based pâtés. In particular, the terpenic compounds showed significant decreases after the thermal stabilization process treatment, due to their degradation and oxidation favored by high temperatures. The thermal stabilization caused, moreover, an increase in volatile compounds deriving from lipid oxidation and Maillard reaction, characterized by low‐sensory thresholds, and from the thermal degradation of carotenoids and fresh tomato‐derived compounds.     

出口炒青绿茶品质提升加工技术研究

针对当前出口炒青绿茶品质存在的“色泽不绿、苦涩味重、有烟焦味”等突出问题进行鲜叶摊放、蒸汽杀青、脱水等关键工艺研究,综合提出长炒青绿茶、圆炒青绿茶加工新工艺。采用新工艺加工的炒青绿茶,汤色改善明显,无烟焦味。长炒青绿茶氨基酸含量提高23.8%,感官审评综合得分提高一个等级(+3.8分);圆炒青绿茶氨基酸和叶绿素含量分别提高5.2%和5.6%。