Oluwafemi J. Caleb

Modified Atmosphere Packaging of Pomegranate Fruit and Arils: A Review

Ongoing global drive for a healthier diet has led to a rise in demand for convenient and fresh food produce, with high nutritional value and free of additives. Minimally fresh processed fruits and vegetables, satisfies the consumers’ perception of a high nutritional quality and convenience produce. Minimally processed fruit and vegetables are susceptible to increased deterioration in quality and microbial infestation due to increase in endogenous enzymatic processes and respiration rate. Modified atmosphere packaging (MAP) technology offers the possibility to retard produce respiration rate and extend the shelf life of fresh produce. However, it is important to correlate the permeability properties of the packing films with the respiration rate of the produce, in order to avoid anaerobic conditions which could lead into fermentation of produce and accumulation of ethanol. Hence, mathematical prediction modelling is now widely applied in the design and development of effective MAP technology in both whole and minimally processed fresh produce. With increasing global interest in postharvest handling and nutrition value of pomegranate, MAP of minimally processed pomegranate arils offers additional innovative tool for optimal use and value addition, including the utilization of lower-grade fruit with superficial peel defects such as; cracks, splits, and sunburnt. This review paper highlights the current status and applications of modified atmosphere packaging in whole fruit and minimally processed pomegranate arils and identifies future prospects.

Modified atmosphere packaging technology of fresh and fresh-cut produce and the microbial consequences ? A review

Modified atmosphere packaging (MAP) technology offers the possibility to retard the respiration rate and extend the shelf life of fresh produce, and is increasingly used globally as value adding in the fresh and fresh-cut food industry. However, the outbreaks of foodborne diseases and emergence of resistant foodborne pathogens in MAP have heightened public interest on the effects of MAP technology on the survival and growth of pathogenic organisms. This paper critically reviews the effects of MAP on the microbiological safety of fresh or fresh-cut produce, including the role of innovative tools such as the use of pressurised inert/noble gases, predictive microbiology and intelligent packaging in the advancement of MAP safety. The integration of Hazard Analysis and Critical Control Points-based programs to ensure fresh food quality and microbial safety in packaging technology is highlighted.

Postharvest treatments of fresh produce

Postharvest technologies have allowed horticultural industries to meet the global demands of local and large-scale production and intercontinental distribution of fresh produce that have high nutritional and sensory quality. Harvested products are metabolically active, undergoing ripening and senescence processes that must be controlled to prolong postharvest quality. Inadequate management of these processes can result in major losses in nutritional and quality attributes, outbreaks of foodborne pathogens and financial loss for all players along the supply chain, from growers to consumers. Optimal postharvest treatments for fresh produce seek to slow down physiological processes of senescence and maturation, reduce/inhibit development of physiological disorders and minimize the risk of microbial growth and contamination. In addition to basic postharvest technologies of temperature management, an array of others have been developed including various physical (heat, irradiation and edible coatings), chemical (antimicrobials, antioxidants and anti-browning) and gaseous treatments. This article examines the current status on postharvest treatments of fresh produce and emerging technologies, such as plasma and ozone, that can be used to maintain quality, reduce losses and waste of fresh produce. It also highlights further research needed to increase our understanding of the dynamic response of fresh produce to various postharvest treatments.

Transpiration rate and quality of pomegranate arils as affected by storage conditions

This study investigated the transpiration rate (TR) of pomegranate (Punica granatum L.) arils under various combinations of temperature (5, 10 and 15°C) and relative humidity (RH) (76, 86 and 96%) during storage. Transpiration rateTR ranged from 1.14 to 16.75 g/kg day across the various combinations of RH and temperature studied. Relative humidityRH had the most significant impact on TR (p < 0.05). Transpiration rateTR increased six-fold when RH was reduced from 96 to 76%, and correlated well with water vapour pressure deficit (WVPD) (R 2 = 96.1%). Aril weight loss increased at higher WVPD. After 8 days of storage, losses in quality attributes of arils were higher with increasing storage temperature and lowering RH. A mathematical model to predict TR as a function of temperature and RH was developed and successfully validated at 8°C. The target water vapour transmission rate of packaging materials for pomegranate arils was found to be 33 to 68 g/m2 day.

Postharvest Handling and Storage of Fresh Cassava Root and Products: a Review

The increase in global demand for healthy food products and initiatives to ensure food security in developing countries has focused on the cultivation of drought-resistant and biofortified cassava varieties. Cassava is a staple root crop grown in subtropical and tropical climates. Cassava flour is gluten free, which can be used as composite flour in essential foods such as bread. Thus, the role of postharvest handling of freshly harvested cassava root is essential, owing to the rapid physiological deterioration of the root soon after harvest. This situation confers a limited shelf life and, thus, creates poor utilization of the cassava root. However, processing cassava root into other food forms such as fufu, garri, starch and high-quality flour enhances stability and long-term storage. This article critically reviewed the postharvest handling, processing and storage of fresh cassava root. Highlighting on the role of storage and minimal processing on sustainable cassava production, various spoilage mechanisms of cassava root were identified. In developing countries, cassava root is a valuable food and energy source, and understanding the role of optimum postharvest handling, processing and storage techniques would alleviate some concerns of food insecurity.

Effects of different maturity stages and growing locations on changes in chemical, biochemical and aroma volatile composition of 'Wonderful' pomegranate juice.

BACKGROUND This study investigated the changes in chemical attributes of pomegranate fruit such as total soluble solids (TSS), titratable acidity (TA), TSS/TA ratio, pH, individual compounds (organic acids and sugars) and volatile composition as affected by fruit maturity status and growing location (Kakamas, Koedoeshoek and Worcester in South Africa). Headspace solid phase microextraction coupled with gas chromatography/mass spectrometry was used for volatile analysis. RESULTS A significant increase in TSS from 14.7 ± 0.6 to 17.5 ± 0.6 °Brix was observed with advancement in fruit maturity, while TA decreased from 2.1 ± 0.7 to 1.1 ± 0.3 g citric acid per 100 mL across all agro-climatic locations investigated. Fruit TSS/TA ratio and pH increased from 7.8 ± 2.6 to 16.6 ± 2.8 and from 3.3 ± 0.1 to 3.6 ± 0.2 respectively during fruit maturation across all agro-climatic locations. Fructose and glucose concentrations increased continually with fruit maturity from 69.4 ± 4.9 to 91.1 ± 4.9 g kg(-1) and from 57.1 ± 4.7 to 84.3 ± 5.2 g kg(-1) respectively. A total of 13 volatile compounds were detected and identified, belonging to five chemical classes. The most abundant volatile in unripe and mid-ripe fruit was 1-hexanol, while 3-hexen-1-ol was highest at commercial maturity. CONCLUSION Knowledge on the impact of fruit maturity and agro-climatic locations (with different altitudes) on biochemical and aroma volatile attributes of pomegranate fruit provides a useful guide for selecting farm location towards improving fruit quality and the maturity stage best for juice processing.

Effects of storage conditions on transpiration rate of pomegranate aril-sacs and arils

This study investigated the effects of temperature (5, 10, 15 and 22 °C) and relative humidity (RH) (76%, 86% and 96%) on the transpiration rate (TR) of pomegranate (Punica granatum L.) cv. Bhagwa fruit fractions, namely arils and aril-sac. Both temperature and RH had significant effects on the TR of fruit fractions. The TR increased with an increase in temperature and decrease in RH, with the fruit fraction stored at 5 °C and 96% RH showing the lowest TR in comparison to other storage conditions. Arils showed higher TR than the aril-sac under all storage conditions. The TR of the arils at 96% RH was in the range 1.42–15.23 g kg−1 d−1, whereas that for the aril-sac was 0.63–9.95 g kg−1 d−1, respectively. The higher TR of fruit arils may be attributed to the larger surface area as compared to the aril-sac whereby some of the arils are covered with the membrane, albedo and peel. A mathematical model was applied and the model adequately predicted the TR for arils and aril-sacs stored at 22 °C and RH 76%, 86% and 96%, with a good correlation between experimental and predicted data.

Modelling the effects of storage temperature on the respiration rate of different pomegra nate fractions

Temperature is one of the main factors that affects fresh produce respiration rate (RR). This study investigated the effects of storage temperature (5, 10, 15 and 22 °C) on the RRs of the pomegranate (Punica granatum L.) ‘Bhagwa’ whole fruit, aril-sacs and arils, and a mathematical model relating temperature to RR was applied. The aril-sacs had the highest RR at all storage temperatures in comparison to the whole fruit and arils. Overall, rates of carbon dioxide production (RCO2) and oxygen consumption (RO2) of the aril-sacs were in the range of 2.95–27.66 ml kg−1 h−1 and 5.49–48.44 ml kg−1 h−1, respectively, whereas those of the whole fruit ranged between 2.66 and 22.97 ml kg−1 h−1 and 3.71 and 33.3 ml kg−1 h−1, respectively, and those of arils were 1.96–18.64 ml kg−1 h−1 and 3.19–28.91 ml kg−1 h−1, respectively. Reducing storage temperature from 22 °C to 5 °C resulted in a reduction in RR of about 74.5% across all samples. Effect of temperature on RR of whole fruit, aril-sacs and arils were adequately predicted by an Arrhenius-type equation (R2 > 97.1%). The model validated RR for arils stored at 22 °C and a good correlation was found between experimental and predicted data.

Respiration and Storage Quality of Fresh-Cut Apple Slices Immersed in Sugar Syrup and Orange Juice

Storing fresh-cut apple slices in suitable fruit juice or sugar syrup is a general practice. However, application of this approach is mainly based on empirical knowledge, while systematic and comprehensive analyses of the relevant effects of this storage technique on keeping quality-related physiological properties of fresh-cut products is still missing. Hence, the aim of this study was to evaluate the impacts of complete immersion of fresh-cut apples in sugar syrup and fruit juice solution on respiratory behaviour and other relevant quality attributes (colour, tissue strength, and soluble solid and acidity). Sugar syrup and pure orange juice showed a high potential to store and protect fresh-cut apples. Results showed that only pure orange juice positively affected the produce quality by preventing browning effects. In addition, sugar syrup of 13.4–20% most effectively prevented browning of apple slices and guaranteed high product quality retention during storage. The application of different liquid media provides a practical means to prevent browning and maintain product quality.

Enzyme kinetics modelling approach to evaluate the impact of high CO2 and super-atmospheric O2 concentrations on respiration rate of pomegranate arils

ABSTRACT Super-atmospheric O2 has been shown to affect respiration rate (RR), but no model describing its effect on RR for pomegranate arils has been reported. This study investigated the effects of four different gas compositions (5 kPa O2, 10 kPa CO2 and 85 kPa N2; 10 kPa O2, 5 kPa CO2 and 85 kPa N2; 70 kPa O2, 10 kPa CO2 and 20 kPa N2; and air) on RR of pomegranate arils (cv. Wonderful) stored at 5°C. Michaelis–Menten enzyme kinetics models were used to investigate the effect of CO2 inhibition on O2 consumption rate. Respiratory quotient was used to determine fermentation threshold. The O2 consumption rate increased from 0.87 to 2.81 mL/kg h, with increase in O2 concentration from 5 kPa to 70 kPa. All enzyme kinetics model parameters adequately described the influence of gas concentration on aril RR with correlation coefficient (R2adj = 81–91%).