Ludlow Richard A, Evans Gareth, Graz Michael, Marti Gracia, Martínez Puri Castillo, Rogers Hilary J, Müller Carsten T
School of Biosciences, Cardiff University, Sir Martin Evans Building, Cardiff CF10 3AX, UK.
Neem Biotech, Units G&H Roseheyworth Business Park, Abertillery NP13 1SX, UK.
Postharvest Biol Technol. 2022 Sep;191:111976. doi: 10.1016/j.postharvbio.2022.111976.
Garlic ( L.) has long been grown for its culinary and health-promoting qualities. The seasonal nature of garlic cropping requires that bulbs be stored for many months after harvest to ensure a year-round supply. During this time, quality is known to deteriorate, and efforts have been made to improve the longevity of stored bulbs. Cold temperatures within the stores prolong shelf life, but fine temperature control is needed to avoid freezing damage or cold induced stress. Here, quality traits (alliinase activity, firmness, and water content) are measured in response to a 96 h - 5 °C cold stress, to simulate the effect of non-isothermic temperature control in a - 1.5 °C warehouse. Volatile organic compounds (VOCs) are measured by thermal desorption gas chromatography time of flight mass spectrometry to identify markers of non-isothermic storage in garlic. 129 compounds were putatively identified and four (L-lactic acid, 2,6-dimethylhetpadecane, 4-methyldodecane, and methylcyclopentane) showed high predictive accuracy for cold stress. VOCs were also sampled directly from a cold storage facility and the whole profile discriminated between sampling time points. Five VOCS were highly predictive for storage time in the warehouse but were different to VOCs previously shown to discriminate between storage times in a laboratory setting. This indicates the need for realistic warehouse experiments to test quality markers.
大蒜（L.）长期以来因其烹饪和促进健康的特性而被种植。大蒜种植的季节性要求在收获后将鳞茎储存数月，以确保全年供应。在此期间，已知品质会下降，人们一直在努力提高储存鳞茎的寿命。储存库内的低温可延长货架期，但需要精确控制温度以避免冻害或冷诱导胁迫。在这里，测量了响应96小时5°C冷胁迫的品质性状（蒜氨酸酶活性、硬度和含水量），以模拟-1.5°C仓库中变温控制的效果。通过热脱附气相色谱飞行时间质谱法测量挥发性有机化合物（VOCs），以识别大蒜非等温储存的标志物。初步鉴定出129种化合物，其中四种（L-乳酸、2,6-二甲基十七烷、4-甲基十二烷和甲基环戊烷）对冷胁迫具有较高的预测准确性。VOCs也直接从冷藏设施中采样，整个图谱在不同采样时间点之间有区别。五种VOCs对仓库储存时间具有高度预测性，但与之前在实验室环境中区分储存时间的VOCs不同。这表明需要进行实际的仓库实验来测试品质标志物。
