Bruise damage measurement and analysis of fresh horticultural produce-A review

Bruising is the most common type of mechanical damage affecting fresh horticultural produce, and reduces quality to the consumer and income to fruit and vegetable industries. Bruising can occur during harvest and at all stages of postharvest handling, especially during packhouse operations, transport and storage, and is one of the major physical defects contributing to downgrading and postharvest loss of fresh horticultural produce. Understanding susceptibility or resistance of produce to bruising is important in developing strategies for reducing the problem. Bruise quantification can be carried out using destructive manual measurements and subsequent analysis, or using a range of non-destructive techniques. Novel and emerging non-invasive technologies for bruise measurement of fresh horticultural produce include near infrared spectroscopy, hyperspectral imaging, thermal imaging and nuclear magnetic resonance imaging. Various mathematical models used to estimate bruise size are discussed, including the use of instrumented spheres to characterise the bruise potential of postharvest handling systems. A wide range of indices based on mathematical expressions of the physical and mechanical properties of fruit, the bruised portion and the energy of the handling system causing the damage have been proposed and applied to quantify the intensity or potential to damage for different commodities and even for the same commodity. Standardisation of bruise measurement and analysis methods is warranted to permit comparison of research results on the effectiveness of pre- and postharvest treatments to reduce bruising, as well as facilitate inter-laboratory traceability of data.