Seasonal variation in chemical composition, aroma volatiles and antioxidant capacity of pomegranate during fruit development

This study was conducted to investigate compositional changes and antioxidant capacities of pomegranate fruit (‘Bhagwa’ and ‘Ruby’) at five distinct stages of maturity over two growing seasons. Total soluble solids (TSS), pH, titratable acidity (TA), phenolic concentrations, antioxidant capacity and aroma volatile constituents were investigated. Principal component analysis (PCA) and Pearson correlation were used to visualize the changes in major chemical indices and the relationship among them. Results show that major compositional changes in fruit are developmentally regulated. Significant increases in total soluble solids (TSS), coupled with significant decline in titratable acidity (TA) and total phenolics (TP) occurred with advancing maturity. Fruit at advanced maturity stages were characterized by intense pigmentation of peel and aril, which coincided with maximum accumulation of anthocyanins. TSS and TA showed strong relationships with most of the chemical indices, each showing significantly (p < 0.05) strong correlations with phenolic components as well as with the antioxidant capacity (FRAP and DPPH) measured. There were no significant (p < 0.05) seasonal effects on juice absorbance (colouration) and TA for ‘Bhagwa’ as well as juice absorbance, TSS, TSS/TA and BrimA for ‘Ruby’. In combination, the identified maturity indices (absorbance, TSS, TSS:TA and BrimA level) would account for the evolution of juice colour, flavour and taste. The identified maturity indices for each cultivar could aid the search for reliable maturity markers to determine fruit readiness for harvest.Keywords: Antioxidant capacity, BrimA, ripeness, seasonality, pomegranate, South Africa.African Journal of Biotechnology Vol. 12(25), pp. 4006-401

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

Harvest and postharvest factors affecting bruise damage of fresh fruits

CITATION: Hussein, Z., Fawole, O. A. & Opara, U. L. 2020. Harvest and Postharvest Factors Affecting Bruise Damage of Fresh Fruits. Horticultural Plant Journal, 6(1):1-13, doi:10.1016/j.hpj.2019.07.006.The original publication is available at https://www.sciencedirect.com/journal/horticultural-plant-journalFresh fruits are susceptible to bruising, a common type of mechanical damage during harvest and at all stages of postharvest handling. In quest of developing and adoption of strategies to reduce bruise damage, it is of utmost importance to understand major factors influencing bruise susceptibility of fresh produce at these stages. This review presents a critical discussion of factors affecting bruising during harvest and postharvest handling of fresh fruits. Excessive compression forces during harvesting by handpicking or machines, and a series of impacts during harvesting, transport and packhouse operations can cause severe bruise damage. The review has further revealed that bruising is dependent on a number of other factors such as produce maturity, ripening, harvest time (during the day or season) and time lapse after harvest. The susceptibility to bruising is partly dependent on how these factors alter the produce physiological and biochemical properties, and the environmental conditions such as temperature, humidity and several other postharvest treatments. Hence, the successful applications of harvesting techniques by use of trained personnel and proper harvesting equipment are essential to reduce both the incidence and severity of bruising. Furthermore, the careful selection of postharvest handling temperature and other treatments can increase resistance of fresh produce to bruise damage.https://www.sciencedirect.com/science/article/pii/S2468014119301943#:~:text=This%20review%20presents%20a%20critical,can%20cause%20severe%20bruise%20damage.Publishers versio

Fatty acid composition, bioactive phytochemicals, antioxidant properties and oxidative stability of edible fruit seed oil : effect of preharvest and processing factors

CITATION: Kaseke, T., Opara, U. L. & Fawole, O. A. 2020. Fatty acid composition, bioactive phytochemicals, antioxidant properties and oxidative stability of edible fruit seed oil : effect of preharvest and processing factors. Heliyon, 6(9):e04962, doi:10.1016/j.heliyon.2020.e04962.The original publication is available at https://www.sciencedirect.comFruit seed is a by-product of fruit processing into juice and other products. Despite being treated as waste, fruit seed contains oil with health benefits comparable or even higher than the conventional seed oil from field crops. In addition to essential fatty acids, the fruit seed oil is a rich source of bioactive compounds such as tocopherols, carotenoids, flavonoids, phenolic acids and phytosterols, which have been implicated in the prevention of chronic and degenerative diseases such as cancer, diabetes and cardiovascular diseases. The emerging potential of fruit seed oil application in food and nutraceuticals has prompted researchers to study the effect of preharvest and processing factors on the seed oil quality with respect to nutritional qualities, antioxidant compounds and properties. Herein, the effect of cultivar, fruit-growing region, seeds pretreatment, seeds drying and seed oil extraction on tocopherols, polyphenols, phytosterols, carotenoids, fatty acids, antioxidant activity and oxidative stability of the fruit seed oil is critically discussed. Understanding the influence of these factors on seed oil bioactive phytochemicals, nutritional qualities and antioxidant properties is critical not only for genetically improving the oilseeds plants with desired characteristics, but also in seed oil processing and value addition. Therefore, preharvest and processing factors are essential considerations when determining the application of fruit seed oil.National Research Foundation of South Africa (Grant Numbers: 64813).Publisher's versio

Evaluating the displacement field of paperboardpackages subjected to compression loading using digital image correlation (DIC)

CITATION: Fadiji, T.; Coetzee, C. J. & Opara, U. L. 2020. Evaluating the displacement field of paperboard packages subjected to compression loading using digital image correlation (DIC). Food and Bioproducts Processing, 123:60-71. doi:10.1016/j.fbp.2020.06.008The original publication is available at https://www.journals.elsevier.com/food-and-bioproducts-processingDigital image correlation (DIC) is a full-field non-contact optical technique for measuring displacements in experimental testing based on correlating several digital images taken during the test, particularly images before and after deformation. Application of DIC cuts across several fields, particularly in experimental solid mechanics; however, its potential application to paperboard packaging has not been fully explored. To preserve fresh horticultural produce during postharvest handling, it is crucial to understand how the packages deform under mechanical loading. In this study, 3D digital image correlation with two cameras and stereovision was used to determine the full-field displacement of corrugated paperboard packaging subjected to compression loading. Strain fields were derived from the displacement fields. Results obtained from the displacement fields showed the initiation and development of the buckling behaviour of the carton panels. The displacement was observed to be largely heterogeneous. The displacement field in the horizontal direction was smaller compared to that of vertical and out-of-plane directions. In addition, the strain variation increased as load increased, which could be a precursor to material failure. The technique proved to be efficient in providing relevant information on the displacement and strain fields at the surface panels of corrugated paperboard packages used for handling horticultural produce. In addition, it offers prospects for improved mechanical design of fresh produce packaging.https://www.sciencedirect.com/science/article/pii/S0960308520304430Publishers versio

Effects of storage conditions and duration on physicochemical and microbial quality of the flour of two cassava cultivars (TME 419 and UMUCASS 36)

This study investigated the effects of storage conditions: cool (15 ± 1°C, 90% relative humidity (RH)), ambient (23 ± 2°C, 60% RH) and higher (38 ± 2°C, 60% RH) on changes in physicochemical quality attributes of two cassava flour cultivars (TME 419 and UMUCASS 36) packaged in paper bags and stored for 12 weeks. Physicochemical and microbial qualities were studied at weeks 0, 4, 8 and 12. Moisture content decreased from 12.0% to 7.1% and 9.8% to 6.8% in cultivars ‘TME 419’ and ‘UMUCASS 36’, respectively. Carotenoid content was higher in cultivar (cv.) ‘UMUCASS 36’ (2.5 ± 0.10 mg/g) compare to cv. ‘TME 419’ (1.8 ± 0.11 mg/g). Colour indices of the cassava flour were significantly influenced by storage duration. A slight decrease in microbial load from 5.4 to 4.8 log CFU/g was observed, with increase in temperature from 15°C to 38°C at the end of storage. The ambient storage condition best maintained nutritional and physicochemical quality.Este estudio investigó los efectos de las condiciones de almacenamiento: frío (15 ± 1°C, 90% humedad relativa (RH); ambiente (23 ± 2°C, 60% RH); y alta (38 ± 2°C, 60% RH) en los cambios en los atributos cualitativos fisicoquímicos de dos cultivares de harina de mandioca (TME 419 y UMUCASS 36) empaquetados en bolsas de papel y almacenados durante 12 semanas. Se estudió la calidad fisicoquímica y microbiana en las semanas 0, 4, 8 y 12. El contenido de humedad disminuyó de 12,0 a 7,1% y de 9,8 a 6,8% en los cultivares ‘TME 419’ y ‘UMUCASS 36’, respectivamente. El contenido en carotenoides fue mayor en el cv. ‘UMUCASS 36’ (2,5 ± 0,10 mg/g) en comparación con el cv. ‘TME 419’ (1,8 ± 0,11 mg/g). Los índices de color de la harina de mandioca estuvieron influenciados significativamente por la duración del periodo de almacenamiento. Se observó un ligero descenso en la carga microbiana de 5,4 a 4,8 log CFU/g, con un aumento en la temperatura de 15°C a 38°C al final del periodo de almacenamiento. El almacenamiento a temperatura ambiente fue el que mantuvo una mejor calidad nutricional y fisicoquímic

Efficacy of edible coatings in alleviating shrivel and maintaining quality of Japanese plum (prunus salicina lindl.) during export and shelf life conditions

CITATION: Fawole, Olaniyi Amos, Riva, Shannon Claudia & Opara, Umezuruike Linus. 2020. Efficacy of edible coatings in alleviating shrivel and maintaining quality of Japanese plum (prunus salicina lindl.) during export and shelf life conditions. Agronomy, 10(7):1023, doi.org/10.3390/agronomy10071023.The original publication is available at: https://www.mdpi.comThe effect of six edible coatings were investigated on the ability to alleviate shrivel and extend shelf life of plums. Fruit were subjected to a simulated shipping period (−0.5 ± 2 ◦C and 90 ± 5% relative humidity (RH)) for five weeks and a subsequent shelf life period (20 ± 2 ◦C and 80 ± 5% RH) for 20 d. Overall, the study showed that it is possible to alleviate shrivel and also extend shelf life of plum (‘African Delight™’) at export and shelf life conditions. Amongst the edible coatings investigated, the findings in fruit coated with gum arabic and the commercial products were comparable and promising for postharvest preservation of the investigated plum cultivar. The coatings showed a moderate delay of fruit ripening, significantly reduced weight loss and shrivel development, allowing for the export of fruit over a long distance (five weeks) and up to 20 d of shelf life.Publisher's versio

Evaluation of the airflow characteristics, cooling kinetics and quality keeping performances of various internal plastic liners in pomegranate fruit packaging

CITATION: Lufu, R. et al. 2020. Evaluation of the airflow characteristics, cooling kinetics and quality keeping performances of various internal plastic liners in pomegranate fruit packaging. Food Packaging and Shelf Life, 26. doi:10.1016/j.fpsl.2020.100585.The original publication is available at https://www.sciencedirect.com/journal/food-packaging-and-shelf-lifeThere is a trade-off to be optimised carefully as plastic liners deal with postharvest cooling processes as well as the produce quality and sustainability requirements. Understanding the implementation of plastic liners in the fresh fruit cold chain is required to reconcile the opposing roles. In this paper, the performances of four types of internal packaging plastic liners were studied. The airflow characteristics, cooling rate, cooling uniformity and quality keeping performances were measured. Cases: no liner, non-perforated liner, micro-perforated liner, macro perforated liner with 2 mm diameter holes, macro perforated liner 4 mm diameter holes were investigated. Generally, the liners delayed the cooling rate significantly. Non-perforated and micro-perforated liners are similar in terms of airflow resistance and cooling rate, both delayed the optimum cooling time by 5 h compared to the plastic-free case. On the other hand, macro-perforated liners cause a delay of only 3 h.https://www.sciencedirect.com/science/article/pii/S2214289420306037Publishers versio

Classification learning of latent bruise damage to apples using shortwave infrared hyperspectral imaging

Bruise damage is a very commonly occurring defect in apple fruit which facilitates disease occurrence and spread, leads to fruit deterioration and can greatly contribute to postharvest loss. The detection of bruises at their earliest stage of development can be advantageous for screening purposes. An experiment to induce soft bruises in Golden Delicious apples was conducted by applying impact energy at different levels, which allowed to investigate the detectability of bruises at their latent stage. The existence of bruises that were rather invisible to the naked eye and to a digital camera was proven by reconstruction of hyperspectral images of bruised apples, based on effective wavelengths and data dimensionality reduced hyperspectrograms. Machine learning classifiers, namely ensemble subspace discriminant (ESD), k-nearest neighbors (KNN), support vector machine (SVM) and linear discriminant analysis (LDA) were used to build models for detecting bruises at their latent stage, to study the influence of time after bruise occurrence on detection performance and to model quantitative aspects of bruises (severity), spanning from latent to visible bruises. Over all classifiers, detection models had a higher performance than quantitative ones. Given its highest speed in prediction and high classification performance, SVM was rated most recommendable for detection tasks

Prediction of ‘Nules Clementine’ mandarin susceptibility to rind breakdown disorder using Vis/NIR spectroscopy

The use of diffuse reflectance visible and near infrared (Vis/NIR) spectroscopy was explored as a non-destructive technique to predict ‘Nules Clementine’ mandarin fruit susceptibility to rind breakdown (RBD) disorder by detecting rind physico-chemical properties of 80 intact fruit harvested from different canopy positions. Vis/NIR spectra were obtained using a LabSpec® spectrophotometer. Reference physico-chemical data of the fruit were obtained after 8 weeks of storage at 8 °C using conventional methods and included RBD, hue angle, colour index, mass loss, rind dry matter, as well as carbohydrates (sucrose, glucose, fructose, total carbohydrates), and total phenolic acid concentrations. Principal component analysis (PCA) was applied to analyse spectral data to identify clusters in the PCA score plots and outliers. Partial least squares (PLS) regression was applied to spectral data after PCA to develop prediction models for each quality attribute. The spectra were subjected to a test set validation by dividing the data into calibration (n = 48) and test validation (n = 32) sets. An extra set of 40 fruit harvested from a different part of the orchard was used for external validation. PLS-discriminant analysis (PLS-DA) models were developed to sort fruit based on canopy position and RBD susceptibility. Fruit position within the canopy had a significant influence on rind biochemical properties. Outside fruit had higher rind carbohydrates, phenolic acids and dry matter content and lower RBD index than inside fruit. The data distribution in the PCA and PLS-DA models displayed four clusters that could easily be identified. These clusters allowed distinction between fruit from different preharvest treatments. NIR calibration and validation results demonstrated that colour index, dry matter, total carbohydrates and mass loss were predicted with significant accuracy, with residual predictive deviation (RPD) for prediction of 3.83, 3.58, 3.15 and 2.61, respectively. The good correlation between spectral information and carbohydrate content demonstrated the potential of Vis/NIR as a non-destructive tool to predict fruit susceptibility to RBD