Browsing by Author "Lotze, E."

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    Are the attitudes and practices of foodservice managers, catering personnel and students contributing to excessive food wastage at Stellenbosch University?
    (Co-published by Medpharm Publications, NISC (Pty) Ltd and Taylor & Francis Group, 2017) Marais, M. L.; Smit, Y.; Koen, N.; Lotze, E.
    Objective: The aim was to investigate factors contributing to food wastage by Stellenbosch University (SU) students in selected residences, and to determine the attitudes and practices of students and catering personnel impacting on food waste and a sustainable environment. Design: Cross-sectional, descriptive study. Setting: Stellenbosch University, Western Cape. Subjects: Six foodservice managers, 63 catering personnel and 517 students participated in the study. Outcome measures: A weighed-food wastage study was conducted at seven selected residences during lunch and supper on three non-consecutive weekdays. Food service managers (FSMs) and catering personnel completed interviewer-administered questionnaires, while SU students completed an electronic survey. Results: Ninety percent of students preferred the standard menu options, despite a relatively high average plate waste of 16.9%. More production waste was generated during lunch than supper. The male residence generated more plate waste. Even though students requested larger servings of vegetables, the wastage of these items was high. Factors contributing to wastage were the booking system, menus and serving style, meal plan stipulating the serving of dessert and serving of a large starch portion. All FSMs and 88.5% catering personnel considered it important to reduce food wastage to a minimum. Conclusion: Education of catering personnel and students regarding food waste reduction measures is crucial. A representative forum including students, catering companies and faculty management should be involved when seeking solutions to reduce food wastage and improve communication. By implementing these strategies, a university-wide culture of sustainability with a focus on food waste reduction can be developed and nurtured.
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    Early prediction of ripening and storage quality of pear fruit in South Africa
    (International Society for Horticultural Science -- ISHS, 2005-04) Lotze, E.; Bergh, O.
    Maturity index records for the principal pear cultivars in the two most important pear producing areas in South Africa were compiled to study the fluctuation in total soluble solids (TSS), fruit firmness and starch breakdown during consecutive seasons. Temperatures (heat units, hu), sunlight hours (ssh), fruit size (diameter), days after bloom (dafb) and soil type were used to calculate the rate of change in TSS levels, firmness and starch breakdown during the last five to six weeks before the picking date. These variables were shown to have an effect on the internal fruit quality. High temperatures were found to result in a faster drop in firmness levels and increased sunlight hours improved the TSS levels. Orchards on sandy soils showed consistently lower TSS levels and firmness when different orchards were compared during consecutive seasons. Equations were fitted to the data for each cultivar and area to develop models for the prediction of the different indices. The predicted rates of change of the different indices were compared with the actual values to test the accuracy and proved to explain more than 80% of the variation during consecutive seasons. The results also showed that the rate of change for these indices could be estimated as early as the middle of December. These models are considered important tools to assist growers, pack houses and marketers in identifying seasons when fruit will have a short shelf life. Picking dates, cold storage and marketing can be adapted to ensure the best possible fruit quality.
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    Using sap flow data to assess variations in water use and water status of apple orchards of varying age groups in the Western Cape Province of South Africa
    (Water Research Commission, 2020-04) Mobe, N. T.; Dzikiti, S.; Volschenk, T.; Zirebwa, S. F.; Ntshidi, Z.; Midgley, S. J. E.; Steyn, W. J.; Lotze, E.; Mpandeli, S.; Mazvimavi, D.
    No accurate quantitative information currently exists on how water use of apple (Malus domestica) orchards varies from planting to full-bearing age, leading to poor irrigation and water allocation decision making. This study sought to address this knowledge gap by investigating how the water use and tree water status vary with canopy cover, cultivar, and climatic conditions in 12 orchards growing in prime apple-producing regions in South Africa. The orchards were planted to the Golden Delicious/Golden Delicious Reinders cultivars which are widely planted in South Africa and the Cripps’ Pink/Cripps’ Red/Rosy Glow which are high-value late- season cultivars. The performance of two transpiration reduction coefficients, one based on sap flow (Ksf) and the other based on soil water depletion (Ks) (FAO approach) were evaluated against the midday stem water potential (MSWP) in all the orchards. While canopy cover had a clear effect on the whole-tree sap flow rates, there were no significant differences in the transpiration per unit leaf area among the cultivars. The daily average sap flux density under unstressed conditions was highest (~284 cm3∙cm–2) in the medium canopy cover orchards (30–44% fractional cover), followed by the mature orchards (~226 cm3∙cm–2), and was lowest in the young orchards (~137 cm3∙cm–2). Canopy cover rather than growing season length had a greater effect on seasonal total water use. Peak daily orchard transpiration ranged from 1.7 mm for young Golden Delicious Reinders trees to 5.0 mm in mature Golden Delicious trees that were maintained with large canopies to reduce sunburn damage to the fruit. For the red cultivars, the peak daily transpiration ranged from 2.0 to 3.9 mm, and the mature trees were maintained with less dense canopies to facilitate the development of the red fruit colour. The less dense canopies on the red cultivars had water-saving benefits since the seasonal total transpiration was lower relative to the Golden Delicious cultivar. The sap flow derived stress coefficient was strongly correlated to the MSWP (R2 ~ 0.60–0.97) in all the orchards while Ks was not able to detect plant stress due to over-irrigation.