Heat and Mass Transfer, and Volume Variations in Banana Slices during Convective Hot Air Drying: An Experimental Analysis

Silva

Food Processing Preservation

et al. 2021

Self Cite

Incorporation of probiotic bacteria in food is a challenge for the industry, given the sensitivity of probiotic cultures to process conditions. The objective of this study was to coat papaya slices with probiotic filmogenic solution to obtain dehydrated probiotic papaya slices. The probiotic filmogenic solution was applied as an edible coating on papaya slices before drying operation at temperatures of 50, 60, and 70°C. The Page model showed the best fit for all kinetics (R² > 0.9988). The use of filmogenic solution to incorporate the probiotic in papaya slices showed satisfactory results, with a reduction of 1.30 LogCFU g −1 at the end of drying at 70°C, reduced shrinkage, resulting in greater conservation of their structure and compounds phenolics. The thermodynamic properties indicate that the coated papaya slices need more energy to start the diffusion process and have a darker color and firmer texture profile. Novelty impact statement:The difference of this study is the evaluation of the potential use of a filmogenic solution based on gelatin and inulin in the incorporation of probiotic in dried fruit. In addition, the use of edible coating as a pretreatment for drying fruits gives interesting technological characteristics to the dried product, increasing its nutritional value.

“…A phenomenon similar to that observed here was described by Farias et al. (2020) in the study of heat and mass transfer and volume variations in banana slices during convective drying.…”

Section: Resultssupporting

confidence: 90%

Section: Shrinkagesupporting

confidence: 87%

Probiotic coating applied to papaya slices for high quality snack production by convective drying

Silva

Food Processing Preservation

et al. 2021

Self Cite

“…Initially, thermal stress undergoes swift escalation, and its maximum value (4.57 kPa) occurs at the instant when the temperature gradient reaches its peak. Subsequently, with the extension of the drying period, thermal stress gradually recedes as the temperature gradient declines (Farias et al, 2020). It is below 1.85 kPa after 60 min and below 0.34 kPa after 180 min.…”

Section: Resultsmentioning

confidence: 99%

Hot‐air drying of corn kernels: Drying kinetics and quality improvement

et al. 2023

Background and Objectives: During the hot-air drying process of corn kernels, excessive stress can cause cracks to develop. For this reason, it's essential to identify the optimum parameters that can minimize stress during hot-air drying. Findings: In this study, a three-dimensional fitness model was established based on the average geometric size of corn kernels. Additionally, a hot-air drying model was constructed on the basis of heat and mass transfer, stress-strain theory, and conservation law of heat and mass transfer. Simulated calculations of heat and mass transfer were performed to obtain the temperature and moisture gradient distribution. This distribution was then coupled with a stress model to reveal the variation of drying stress. Verification experiments were conducted on the drying model. The results indicated that the temperature and moisture gradient were symmetrically distributed about the geometric center of corn kernels. At symmetrical positions about the geometric center, their sizes were almost equal but their directions are opposite. The thermal stress and moisture gradient stress showed the fact of larger surface but smaller interior of corn kernels. Furthermore, they both increased rapidly in the initial stage and then slowly decreased. The maximum value of thermal stress was 4.57 kPa, and the maximum value of moisture gradient stress was 0.49 MPa.Conclusions: Mass transfer plays a significant role in the hot-air drying process, and cracks can develop as a result of excessive moisture gradient stress.To mitigate these issues, it's important to increase the air humidity in a controlled manner to significantly reduce the total stress. The maximum error in temperature between simulated and experimental results was 8.5%. This suggests that our drying model can be effectively utilized to explore temperature gradient, moisture gradient, and stress distribution of corn kernels.Significance and Novelty: This study provides insights into the mechanism of stress generation that occurs during the hot-air drying process of corn kernels. Our analysis indicates that properly increasing the air humidity can significantly reduce drying stress and consequently prevent the formation of cracks. This ultimately leads to improved product quality and economic value.

J Food Process Engineering

“…(MR = 0.2) (n = 3 replicates) (Farias et al, 2020;Nguyen & Price, 2007). The moisture content is defined as the percentage on wet basis (%w.b.).…”

Section: Sample Preparation and Drying Kinetics Studymentioning

confidence: 99%

“…The structure inside PA banana is a non-porous solid material, so the moisture content relates to the structure while it is dried and there will not be a constant drying rate period like there would be with free water in connected pore space (de Lima, Farias Neto, & Silva, 2012;de Lima, Queiroz, & Nebra, 2002). In many previous studies (de Souza, de Andrade, & Rios, 2019;Farias et al, 2020;Maskan, 2000;Rahman, Ahmed, & Islam, 2018;Smitabhindu, Janjai, & Chankong, 2008;Thuwapanichayanan, Prachayawarakorn, & Soponronnarit, 2008), the drying of PA bananas has stopped microorganism activity when the final moisture content of PA banana is below 13%w.b. ; moreover, temperature and drying time are important parameters that affect the physical structure after drying.…”

mentioning

confidence: 99%

Hybrid infrared with hot air drying of Pisang‐Awak banana: Kinetics and shrinkage quality

Puangsuwan

Jumrat

Muangprathub

et al. 2021

The purpose of this study was to develop the prototype drying system for drying the Pisang-Awak (PA) banana. It was designed and implemented to study the drying kinetics in each drying mode: hot air drying (HA), infrared drying (IR), and hybrid drying (Hy). The experimental results were fit with simulation results from the finite element method (FEM). Two statistical parameters, the coefficient of determination R 2 and the root mean square error RMSE ð Þ, were used to assess the fit between experimental results and simulation results, and their respective ranges were 0.960-0.997 and 0.014-0.050. For PA banana drying the most suitable drying mode is hybrid, combining 1.5 m/s flow of hot air and IR heating at 60 C drying temperature. The axial and radial shrinkages of PA banana were the largest in Hy mode at 60 C, namely 18.2 and 27.3%, respectively, and this choice gave the best/lowest specific energy consumption (SEC) for drying performance and the best final dried PA banana. Practical ApplicationsThe understanding of the drying kinetics and shrinkage properties of the dried PA banana is important for the choice of drying process because these reflect the quality of the dried product and help an engineer to design the drying system. Therefore, the empirical mathematical modeling of the drying process serves a crucial role in the food industry sector. These results can be used to quantify temperature and moisture content as functions of drying time to monitor the drying process of PA banana, saving energy and time. | INTRODUCTIONIn the years 2017-2019, the top three produced bananas in Thailand were Pisang-Awak (PA) banana, Banana, and Pisang-Mas banana, at respectively 3,993, 903, and 670 ktons (Department of Agricultural Extension, n.d.). The PA banana is an economic plant widely used in Thai dessert recipes. Consuming two such bananas can give enough energy for up to 90 min of exercise, with also large doses of dietary fiber, vitamins, and minerals. Benefits of bananas to the human body include reducing bad breath, providing anti-oxidants, and relief to constipation, morning sickness, hemorrhoids, obesity, high blood pressure, broken capillaries, and so on (Robinson & Galan Sauco, 2011).Growing bananas gives year-round production in Thailand, but in some seasons the production can exceed the demand, while the shelf life of bananas is only 5 to 7 days before spoilage by the enzymes in them (Naknaen, Charoenthaikij, & Kerdsup, 2016;Sankat & Castaigne, 2004). Processing banana is an alternative way to address this problem.Drying is one way to preserve food products for prolonged storage. It removes water or moisture under controlled conditions by the use of heat. The low moisture level then inhibits the growth of harmful microbes, inactivates enzymes, and helps avoid toxins, parasites, and various insects (Bala, Mondol, Biswas, Das Chowdury, & Janjai, 2003). The design of a drying system requires the use of