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Dropping macadamia nuts‐in‐shell reduces kernel roasting quality
Author(s) -
Walton David A,
Wallace Helen M
Publication year - 2010
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.4063
Subject(s) - macadamia nut , roasting , postharvest , water content , moisture , browning , shell (structure) , food science , horticulture , chemistry , pulp and paper industry , materials science , composite material , metallurgy , biology , geotechnical engineering , engineering
BACKGROUND: Macadamia nuts (‘nuts‐in‐shell’) are subjected to many impacts from dropping during postharvest handling, resulting in damage to the raw kernel. The effect of dropping on roasted kernel quality is unknown. Macadamia nuts‐in‐shell were dropped in various combinations of moisture content, number of drops and receiving surface in three experiments. After dropping, samples from each treatment and undropped controls were dry oven‐roasted for 20 min at 130 °C, and kernels were assessed for colour, mottled colour and surface damage. RESULTS: Dropping nuts‐in‐shell onto a bed of nuts‐in‐shell at 3% moisture content or 20% moisture content increased the percentage of dark roasted kernels. Kernels from nuts dropped first at 20%, then 10% moisture content, onto a metal plate had increased mottled colour. Dropping nuts‐in‐shell at 3% moisture content onto nuts‐in‐shell significantly increased surface damage. Similarly, surface damage increased for kernels dropped onto a metal plate at 20%, then at 10% moisture content. CONCLUSION: Postharvest dropping of macadamia nuts‐in‐shell causes concealed cellular damage to kernels, the effects not evident until roasting. This damage provides the reagents needed for non‐enzymatic browning reactions. Improvements in handling, such as reducing the number of drops and improving handling equipment, will reduce cellular damage and after‐roast darkening. Copyright © 2010 Society of Chemical Industry