Advances in design and performance evaluation of fresh fruit ventilated distribution packaging : a review

CITATION: Mukama, M. et al. 2020. Advances in design and performance evaluation of fresh fruit ventilated distribution packaging : a review. Food Packaging and Shelf Life, 24. doi:10.1016/j.fpsl.2020.100472The original publication is available at https://www.sciencedirect.com/journal/food-packaging-and-shelf-lifeThis review was initiated to realise the state-of-the art in optimising the ventilation and structural requirements of corrugated packaging carton design. Researchers have been using computational methods: computational fluid dynamics, particularly, the finite volume method, to analyse the airflow and heat transfer performances, and computational structural dynamics, particularly, the finite element method, to analyse the loss of compression strength due to vent-holes. Models are validated using actual testing: wind tunnel based forced air cooling system to study the produce cooling kinetics and box compression test machine for the package industry to study the structural dynamics. Studies on the rate and uniformity of produce cooling and the loss of structural strength in corrugated cartons as a function of size, shape, and location of vent-holes are reviewed. Based on experimental data, results show that the loss in strength can range between 10–40 % on addition of vent and hand holes on cartons, and reasonable increase in cooling rates is only achieved with increase in carton face ventilation area only up to 7–8 %. With regards to internal packaging components, increasing awareness of consumers to the environmental degradation of especially disposable plastic packaging means packers and suppliers must devise means to cut back and eventually eliminate plastic packaging from fruit and vegetables.https://www.sciencedirect.com/science/article/pii/S2214289419306519?via%3DihubPublishers versio

Depression and associated factors among prisoners in Bahir Dar Prison, Ethiopia

Abstract Background Globally there is a rapid increase in prison population, and one out of nine inmates suffers from mental disorders like depression. In Ethiopia, although a mental health strategy is in place, little attention is given to prisoners and studies which focus on depression among prisoners are still scarce. The aim of this study was to assess the prevalence of depression and factors associated with it among prisoners. Method Across-sectional study was conducted from October 5 to 28, 2016 in Bahir Dar city. Simple random sampling technique was used to select 402 prisoners. Depression was measured using Patient Health Questionnaire, nine item version (PHQ-9) at a cut point of five. Data on socio-demographic characteristics, behavioral factors, perceived general health, and prison situation variables were collected using structured questionnaire. The data were collected by trained interviewers. SPSS version 20 was used to analyze the data. Binary logistic regression was used to identify predictors of depression. Result The prevalence of depression was 45.5% (95%CI: 40.5–50.5%). In the final model, having children [Adjusted Odds Ratio (AOR) = 2.48; 95%CI: 1.60–3.83], health satisfaction rated as moderate [AOR = 3.20; 95%CI: 1.12–9.00] or dissatisfied [AOR = 1.63; 95%CI: 1.02–2.62] compared to satisfied, being sentenced for more than 5 years [AOR = 2.31; 95%CI: 1.01–5.25] or 1–5 years [AOR = 3.04; 95%CI: 1.2–7.71] were positively associated with depression. Conclusion High prevalence of depression was found among prisoners. Those with poor general health, long years of imprisonment, and concerns of children were the most vulnerable. Strengthening mental health services of prisons is critically required

Modelling the kinetics of the application process of 1-Methylcyclopropene (1-MCP) as a food preservation method for fruit

Abstract Maintaining quality and delaying over-ripening and senescence are the main goals in handling and storage of fruits and vegetables. Conventionally, control of temperature and humidity and selective use of controlled or modified atmospheres have helped to obtain these goals. Nowadays new methods for delaying postharvest senescence and deterioration of perishable fruits, vegetables, potted plants, and cut flowers are emerging. These include the molecular modification of ripening physiology and the use of compounds that specifically target and inhibit ethylene responsiveness. One of these compounds, 1-methylcyclopropene (1-MCP), has been shown to suppress ethylene responses and extend the postharvest shelf life and quality of numerous fruits and vegetables. Modeling the diffusion and transport of 1-MCP gas in storage rooms for fruits and vegetables may be a potential tool to investigate several situations. Developing such model require knowledge about diffusion and reaction coefficients of 1-MCP gas in the various materials, including the fruit, present in storage rooms. A model governing the diffusion and adsorption behavior of 1-MCP gas in fruits and non target materials found in apple fruit storage rooms is presented. The model is used to estimate kinetics parameters using time-dependent profiles obtained from jar tests on the depletion of 1-MCP gas by samples of wet and dry solid materials. Materials included in the investigation were: Golden delicious apple and bin construction materials [high density polyethylene (HDPE), slightly weathered oak, Poplar wood and cardboard]. The 1-MCP gas diffusion parameters for dry and wet materials were successfully estimated. The model will be used to compute the distribution of 1-MCP in storage rooms and assess the uniformity and dosing of application for different configurations.status: accepte

Transport properties of fermentation metabolites inside ‘Conference’ pear fruit

© 2016 Elsevier B.V. Ethanol, acetaldehyde and ethyl acetate are the major fermentation metabolites in 'Conference' pear fruit under severe hypoxic or anoxic storage conditions. Predicting diffusion of the fermentation metabolites in fruit tissue will allow to understand the accumulation of the harmful fermentation metabolites under anoxic conditions and to predict their release during reoxygenation after anoxia. In this paper, the diffusivity of fermentation metabolites of pear fruit tissue was computed using a multiscale diffusion model and experimentally validated. The effect of temperature on the diffusion of the metabolites inside the fruit was assessed. Simulation results revealed that the cell membrane is an important barrier to diffusion of fermentation metabolites in cortex tissue. The diffusivity of fermentation metabolites across the epidermis was much lower than that of cortex tissue, and was highly affected by the density of lenticels. The diffusivities of fermentation metabolites increased with increasing temperature in both cortex and epidermis tissues.publisher: Elsevier articletitle: Transport properties of fermentation metabolites inside ‘Conference’ pear fruit journaltitle: Postharvest Biology and Technology articlelink: http://dx.doi.org/10.1016/j.postharvbio.2016.01.008 content_type: article copyright: Copyright © 2016 Elsevier B.V. All rights reserved.status: publishe

Model-based design and development of horticultural produce crate from bamboo

AbstractThis study proposes a model-based design and development of ventilated horticultural product crate from bamboo using a validated computational fluid dynamics and finite element analysis models. The models were used to predict the airflow, pressure and temperature distributions, and mechanical integrity of the crate. The model results were validated using experimental results. Results of the newly developed crate were compared to the commonly used conventional wooden crate. The optimal vent area, vent number, and cooling air velocity were found to be 8%, nine vents, and 1.38 m s−1, respectively. Compared to the conventional crate, the improvement in cooling rate, pressure drop, and flow uniformity was 60%, 98%, and 37.9%, respectively. The maximum deformation in the conventional wooden and newly developed crates was 28.483 mm and 0.329 mm, respectively. The results indicate that the newly developed bamboo-based crate has good air ventilation, good cooling, and best in mechanical integrity. We conclude that the improved bamboo crate is a viable alternative to the present post-harvest packaging constraints

Mathematical modelling of blanch-assisted drying of pomegranate (Punica granatum) arils in a hot-air drier

CITATION: Adetoro, A. O., et al. 2020. Mathematical modelling of blanch-assisted drying of pomegranate (Punica granatum) arils in a hot-air drier. Processes, 8(5):611, doi:10.3390/pr8050611.The original publication is available at https://www.mdpi.comPublication of this article was funded by the Stellenbosch University Open Access FundThe effect of blanching conditions on the hot-air drying kinetics of three pomegranates (cvs. “Acco”, “Herskawitz” and “Wonderful”) were assessed. Water blanching conditions considered were 90 °C for 30 s, 90 °C for 60 s, 100 °C for 30 s and 100 °C for 60 s. The drying experiments were carried out at 60 °C, 19.6% relative humidity and at a constant air velocity of 1.0 m s−1. The experimental curves were fitted to seven different drying models. For the Acco cultivar, the drying behaviour was best predicted by the Logarithmic and Page model for blanched (R2 ranging between 0.9966 and 0.9989) and unblanched (R2 = 0.9918) samples, respectively. Furthermore, for the Herskawitz cultivar, Logarithm, Page and Midili models were most suitable for predicting drying behaviour of both blanched and unblanched samples. Also, for the Wonderful cultivar, Logarithm and Midili models were most accurate for predicting the drying behaviour for both blanched and unblanched samples amongst other models. The blanched samples dried faster with shorter drying times: “Acco” (7 h), “Herskawitz” (8 h), and “Wonderful” (7 h), compared to the unblanched samples, which dried after 15, 20 and 11 h, respectively. Effective diffusion coefficient of moisture in pomegranate arils ranged from 4.81 × 10−9 and 1.11 × 10−8 m2 s−1 for the Acco cultivar, for the Herskawitz cultivar; 3.29 × 10−9 and 1.01 × 10−8 m2 s−1 and for the Wonderful cultivar; 5.83 × 10−9 and 1.09 × 10−8 m2 s−1. Overall, blanching resulted in low energy consumption during drying of pomegranate arils. In addition, the Logarithmic model generally showed an appropriate model for blanched samples regardless of cultivar. For unblanched samples, the Page model was more appropriate for “Acco” and “Herskawitz”, while the Midili model was appropriate for “Wonderful”. Therefore, this study provided science-based and practical drying conditions for the investigated pomegranate cultivars.https://www.mdpi.com/2227-9717/8/5/611Publisher's versio

Application of gum arabic and methyl cellulose coatings enriched with thyme oil to maintain quality and extend shelf life of “Acco” pomegranate arils

CITATION: Kawhena, T. G. et al. 2020. Application of gum arabic and methyl cellulose coatings enriched with thyme oil to maintain quality and extend shelf life of “Acco” pomegranate arils. Plants, 9(12):1690, doi:10.3390/plants9121690.The original publication is available at https://www.mdpi.comThe effects of gum arabic (GA; 1.5% w/v) and methyl cellulose (MC; 1% w/v) enriched with thyme oil (TO; 0.25 and 0.5% v/v) on the quality of “Acco” pomegranate arils were studied. Coating treatments, namely, MC, MC + TO0.5%, MC + TO0.25%, GA, GA + TO0.5% and GA + TO0.25% were applied on arils by dipping, and evaluations were made on physicochemical and microbiological quality, phytochemicals and antioxidant capacity of arils stored (5 ± 1 ◦C, 95 ± 2% RH) for 16 days. Dipping arils in GA or MC, both containing TO (0.5% v/v) significantly (p < 0.0001) reduced weight loss and enhanced antioxidant activity (FRAP) (p = 0.0014). However, dipping arils in GA combined with TO (0.25% v/v) had the highest influence on reducing aril respiration rate compared with other treatments. Overall, results showed that application of coatings (GA + TO0.5% and GA + TO0.25%) reduced total yeast and mould and total plate counts and maintained quality up to 8 days of storage. These findings suggest that either GA + TO0.5% or GA + TO0.25% coatings have the capability to extend storage life of “Acco” pomegranate arils.Pomegranate Association of South Africa (POMASA)https://www.mdpi.com/2223-7747/9/12/1690Publisher's versio

Analysis of airflow and heat transfer inside fruit packed refrigerated shipping container: Part II - Evaluation of apple packaging design and vertical flow resistance

In the previous paper (Part I) in this series, a validated 3-D computational fluid dynamics (CFD) model of airflow and heat transfer inside a refrigerated shipping container (reefer) packed with apple was developed using porous media approach. In this paper (Part II), the cooling performance of commonly used package designs used for handling apple was investigated. First, the study computes the aerodynamic and thermodynamic characteristics of three package designs. This confirmed the effect of vertical airflow on the rate and uniformity of cooling inside the reefer. Then, the effects of vertical flow resistance on the rate and uniformity of cooling was further investigated. Adding vent-holes (3.5% vent area) on the bottom face of the package reduced vertical airflow resistance, and reduced the seven-eighth cooling time by 37% compared to a package with no bottom vent-holes. The study demonstrated the significance of vent-holes on the bottom face of packaging boxes and the potential energy saving opportunities in refrigerated transport systems.publisher: Elsevier articletitle: Analysis of airflow and heat transfer inside fruit packed refrigerated shipping container: Part II – Evaluation of apple packaging design and vertical flow resistance journaltitle: Journal of Food Engineering articlelink: http://dx.doi.org/10.1016/j.jfoodeng.2017.02.011 content_type: article copyright: © 2017 Elsevier Ltd. All rights reserved.status: publishe