Sandra Landahl

Spatial and temporal analysis of textural and biochemical changes of imported avocado cv. hass during fruit ripening.

The ripeness degree of climacteric fruits, such as avocado ( Persea americana Mill.), can be correlated with rheological properties. However, there remains little information on not only the postharvest changes in texture of avocado fruit from different origins but also the spatial variation within fruit. In addition, the relationship between changes in texture and composition of fatty acids and major nonstructural carbohydrates (NSCs) of fruit tissue during ripening is unknown. The texture of different horizontally cut slices from individual fruits within a consignment was measured during ripening using a previously unreported technique. The composition of fatty acids and NSCs in fruit mesocarp tissue was determined. The composition of fatty acids and oil and dry matter contents varied significantly according to origin. Significant changes in texture, mannoheptulose and perseitol contents, and linoleic acid percentage were found in avocado fruit flesh during ripening. Spatial variation within fruit was detected in both textural and biochemical characteristics.

Non-destructive and destructive firmness measurements on apples and peaches.

Abstract A non-destructive acoustic impulse response test was performed on different apple varieties at different maturity stages and on recently picked peaches. High natural frequencies were measured solely on fruits with low mass. The firmness was determined destructively on the fruits with the hand-operated penetrometer and a universal testing machine. A weak correlation between the results of the non-destructive and the destructive method could be derived. The stiffness measured with the acoustic impulse response technique tended to change with maturation of the apples. A drop in stiffness in a short time period was ascribed to the weather.

Assuring Potato Tuber Quality during Storage: A Future Perspective

Potatoes represent an important staple food crop across the planet. Yet, to maintain tuber quality and extend availability, there is a necessity to store tubers for long periods often using industrial-scale facilities. In this context, preserving potato quality is pivotal for the seed, fresh and processing sectors. The industry has always innovated and invested in improved post-harvest storage. However, the pace of technological change has and will continue to increase. For instance, more stringent legislation and changing consumer attitudes have driven renewed interest in creating alternative or complementary post-harvest treatments to traditional chemically reliant sprout suppression and disease control. Herein, the current knowledge on biochemical factors governing dormancy, the use of chlorpropham (CIPC) as well as existing and chemical alternatives, and the effects of pre- and post-harvest factors to assure potato tuber quality is reviewed. Additionally, the role of genomics as a future approach to potato quality improvement is discussed. Critically, and through a more industry targeted research, a better mechanistic understanding of how the pre-harvest environment influences tuber quality and the factors which govern dormancy transition should lead to a paradigm shift in how sustainable storage can be achieved.

Rapid methods for extracting and quantifying phenolic compounds in citrus rinds

Abstract Conventional methods for extracting and quantifying phenolic compounds in citrus rinds are time consuming. Rapid methods for extracting and quantifying phenolic compounds were developed by comparing three extraction solvent combinations (80:20 v/v ethanol:H2O; 70:29.5:0.5 v/v/v methanol:H2O:HCl; and 50:50 v/v dimethyl sulfoxide (DMSO):methanol) for effectiveness. Freeze‐dried, rind powder was extracted in an ultrasonic water bath at 35°C for 10, 20, and 30 min. Phenolic compound quantification was done with a high‐performance liquid chromatography (HPLC) equipped with diode array detector. Extracting with methanol:H2O:HCl for 30 min resulted in the optimum yield of targeted phenolic acids. Seven phenolic acids and three flavanone glycosides (FGs) were quantified. The dominant phenolic compound was hesperidin, with concentrations ranging from 7500 to 32,000 μg/g DW. The highest yield of FGs was observed in samples extracted, using DMSO:methanol for 10 min. Compared to other extraction methods, methanol:H2O:HCl was efficient in optimum extraction of phenolic acids. The limit of detection and quantification for all analytes were small, ranging from 1.35 to 5.02 and 4.51 to 16.72 μg/g DW, respectively, demonstrating HPLC quantification method sensitivity. The extraction and quantification methods developed in this study are faster and more efficient. Where speed and effectiveness are required, these methods are recommended.

Spatio-temporal postharvest changes in texture and fatty acid profiles in avocado fruit from different origins

The degree of ripeness of many climacteric fruits, such as avocado, can be correlated with flesh firmness and other rheological properties. However, there remains a paucity of information on not only the postharvest changes in texture of avocado fruit from different origins, but also on the spatial variation in texture within individual fruit. In addition, the relationship between changes in texture and lipid profile of fruit tissue during postharvest ripening is unknown.