The dehydration of paprika with ambient and heated air and the kinetics of colour degradation during storage

Physico-Chemical Properties of Red Pepper (Capsicum annuum L.) as Influenced by Different Drying Methods and Temperatures

An experiment was carried out in the laboratories of the Department of Food Engineering, Department of Vegetable Science, and Department of Plantation Spices Medicinal and Aromatic crops, Bidhan Chandra Krishi Viswavidyalaya (BCKV), West Bengal, India. The work was performed during 2018–2019 and 2019–2020 with different drying methods including sun drying, solar drying and oven drying. In oven drying, different temperatures such as 50, 55, 60, 65, and 70 °C were considered. A randomized complete block design (RCBD) was designed with seven treatments and three replications. Experimental results were significantly varied among the treatments as influenced by different drying methods and temperatures. Minimum time taken (480 min) to reach safe moisture content was recorded in T7 (oven drying at 70 °C), whereas maximum values in color components such as L* value (24.55), a* value (32.14), b* value (20.53), and pungency score (7.85) were recorded in T6 (oven drying at 65 °C). However, the highest texture (1180.81) was observed in T1 (sun drying). Biochemical parameters were significantly varied among the treatments. The maximum amounts of ascorbic acid (56.06 mg/100 g) and oleoresin content (10.72) were found in T3 (oven drying at 50 °C), whereas minimum values of biochemical parameters were recorded by T1 (sun drying) and T2 (solar drying) methods, respectively. Mathematical relationships were found in different drying methods and temperatures. Models such as the Lewis, Page, Modified Page, and Henderson and Pabis models were selected to fit the data. Maximum R2 value (0.9835) was found in both the Page and Modified Page models with similar values of drying method and temperature at 65 °C. This value was the highest among all models in all drying temperatures. However, the lowest χ2, and RMSE values (0.000818 and 0.027261, respectively) were recorded with the Page model.

Environmental sustainability of a pork and bean stew

The aim of this investigation is to quantify the environmental footprint of an industrially produced bean and pork stew produced using a combination of local/imported and fresh/ processed ingredients. The study describes 16 midpoint categories and an aggregated score, calculated following the EC Product Environmental Footprint (PEF) methodology. The carbon footprint of 1 kg of stew amounts to 2.23 kg CO₂ eq., with the production of ingredients (upstream phase) dominating most impact categories (e.g., 68.0% of carbon footprint and 73.5% of the single score), due primarily to the emission intensity of animal products. Although the white beans account for 43.7 wt%, its carbon emissions represent only 18.4% of those generated by the ingredients. However, white beans have a high contribution on other impact categories such as toxicity, acidification, and eutrophication, which are associated with the use of agrochemicals. Despite being imported from Argentina to Spain, transport has a limited contribution to most impact categories (e.g., 18.1% climate change and 12.9% the single score). Despite showing a very high carbon intensity, the contribution of spices to the environmental footprint of the stew is very limited due to the very small amounts consumed. The industrial cooking stage (core phase) contributes to 17.3% of the stew's carbon footprint and 10.6% of the aggregated score, due to emissions derived primarily from the use of natural gas and electricity. Distribution is the activity contributing the most to the consumption stage. The tinplate employed to fabricate the metal cans is responsible for most of the impact associated with the packaging of the stew. However, substituting tinplate with aluminium is not recommended due primarily to the lower environmental savings associated with the recycling of the latter.

Modeling sorption phenomena and moisture migration rates in paprika (Capsicum annuum L.) using physicochemical characteristics

In the present study, the GAB and moisture migration rate models were used to predict the shelf life of paprika under domestic (40 °C and 90% RH) and industrial (5, 10, 15 and 20 °C with 70% RH) storage conditions. The correlations between physicochemical characteristics and moisture content of paprika were developed to estimate the stability of the paprika. The estimated shelf life of low moisture paprika (4.40% dry basis) was found to be 101 and 31 days in HDPE and LDPE packages, respectively when stored in domestic condition. In industrial storage condition, the shelf life prediction was 5.47 years in HDPE and 1.68 years in LDPE packages. The first order kinetic models of extractable color (ASTA) and degree of caking described the quality degradation of paprika during storage. The relative humidity and temperature of the storage environment were significant parameters affecting the stability of paprika. The shelf life of paprika can be extended by storage at or below monolayer moisture content and low temperature.

Optimization of drying process parameters for cauliflower drying

The different sizes (3, 4 and 5 cm) of hybrid variety of cauliflower (variety no. 71) were dehydrated in thin layer at three temperatures of 55, 60 and 65 °C with velocities of 40, 50 and 60 m/min. Dehydrated samples were analyzed for vitamin C, rehydration ratio and browning. Statistical analysis indicated that drying time was dependent on initial size of cauliflower, drying air temperature and velocity, but rehydration ratio was significantly affected by the combined effect of temperature and airflow velocity. Vitamin C content of the dried cauliflower samples were significantly affected by temperature only and non enzymatic browning was function of temperature, airflow velocity, and combined effect of temperature and airflow velocity. Optimization of the drying process parameters for the given constraints resulted in 60.10(0)C, 59.28 m/min, 3.35 cm. The predicted responses for the optimized combination of process parameters were time, vitamin C content, rehydration ratio, and browning values of 491.22 min (time), 289.86 mg/100 g (Vitamin C), 6.91 ( rehydration ratio), and 0.14 (browning), respectively with the desirability factor of 0.787.

A review of thin layer drying of foods: theory, modeling, and experimental results

Drying is a complicated process with simultaneous heat and mass transfer, and food drying is especially very complex because of the differential structure of products. In practice, a food dryer is considerably more complex than a device that merely removes moisture, and effective models are necessary for process design, optimization, energy integration, and control. Although modeling studies in food drying are important, there is no theoretical model which neither is practical nor can it unify the calculations. Therefore the experimental studies prevent their importance in drying and thin layer drying equations are important tools in mathematical modeling of food drying. They are practical and give sufficiently good results. In this study first, the theory of drying was given briefly. Next, general modeling approaches for food drying were explained. Then, commonly used or newly developed thin layer drying equations were shown, and determination of the appropriate model was explained. Afterwards, effective moisture diffusivity and activation energy calculations were expressed. Finally, experimental studies conducted in the last 10 years were reviewed, tabulated, and discussed. It is expected that this comprehensive study will be beneficial to those involved or interested in modeling, design, optimization, and analysis of food drying.

Drying of Red Pepper (Capsicum Annuum): Water Desorption and Quality

Capsicum annuum samples were dried at different air-drying temperatures, ranging from 30 to 90ºC. Modelling of the drying curves was satisfactory when the Page model (average percentage of explained variance was 99.0 ± 0.2%) was used, whereas the Peleg model provided a less accurate simulation (average percentage of explained variance was 91± 14%). Both k and n parameters of the Page’s model exhibited a clear temperature dependence. In fact, n parameter varied linearly with the temperature (r2=0.92), whereas k parameter followed an Arrhenius relationship (r2= 0.96). An activation energy value of ca 27 kJ/mol was estimated using the Page equation. Air-drying temperature influenced the final quality of the dried red pepper (paprika). According to the results, drying within the range of 50 to 75ºC, would be the optimum conditions to achieve a final product with the best colour characteristics (highest ASTA and chroma values) and also, with the highest antioxidant capacity.

Change in the carotenoid and antioxidant content of spice red pepper (paprika) as a function of ripening and some technological factors

A study was conducted to investigate the change in quality attributes of red pepper (paprika) (Capsicum annuum L. var. Km-622) as a function of ripening and some technological factors. Of quality attributes, carotenoids and bioantioxidants (ascorbic acid and tocopherols) have been studied. It was found that the dynamics of fruit ripening with regard to carotenoids and bioantioxidants was influenced to a considerable extent by weather conditions of the production season. A rainy and cool season yielded fruits with more beta-carotene but less diesters of red xanthophylls as compared to those produced in a relatively dry and warm season. The ripening stage at harvest was found to affect the quality of paprika. Harvest at unripe stages (color break or faint red) resulted in a high accumulation of dehydroascorbic acid in the overripe fruits, whereas de novo biosynthesis of carotenoids and tocopherols was partially retarded. Application of pre-drying centrifugation resulted in a marked loss of ascorbic acid, and as a consequence, carotenoid stability was impaired during the storage of ground paprika. Sugar caramelization caused dry pods and ground paprika to retain more pigments and tocopherol as compared to those from control or centrifuged red pepper samples. During the storage of ground paprika, color stability was improved by grinding the seeds with the pericarp.