| With the improvement of living standards in China, refrigerator becomes an indispensable necessity of life in each family. However, the odor resulted either from the new refrigerator itself, or from the food stored in a refrigerator used for long-term, has become a problem concerned more and more seriously. It determined refrigerator odor composition througher SPME/GC/MS, it optimized SPME/GC/MS conditions to determine the best method for measuring refrigerator odor, and it analyzed the refrigerator odor composition with the optimal method. It created "external standard method with sampling bags" for quantitative results of refrigerator odor substance concentration, at the same time, it measured odor components of six kinds of refrigerator materials, for comprehensive analysis of the refrigerator odor source. It analyzed odor changes of the refrigerator under conditions of storing five kinds of typical food in it. Integrated combined with the smell changes of each food, and changes of each food quality during the process, refrigerator odor and their sources in use were obtained. It removed odor of refrigerator itself and peculiar smell in process of use through four kinds of deodorizing methods, meantime, refrigerator odor removal efficiency were analyzed and evaluated. The main conclusions were as follows:1. The optimal method for analysis of the refrigerator odor composition:using50/30μm DVB/CAR/PDMS fiber, absorbed for50min in ambient temperature and desorbed on injection port temperature260℃for3min. Through this method, it analyzed the odor composition of the cooling room, light-degree freezing room, and freezing room, and identified41kinds of substances, in which, aromatic substances accounted for the highest proportion, content of which nearly50%, alkanes, alkenes, followed by20%, in addition, it also contained5-10%of alcohols and esters. As for the material composition analysis,1-pentene and styrene possessed the highest content of50%of the whole refrigerator volatile components. Therefore, aromatics, olefins and alcohols were the main composition of refrigerator odor,1-pentene and styrene were the major contributors to the refrigerator odor composition.2. Aromatic hydrocarbon compounds accounted for the highest concentration in the refrigerator, in particular,762.99μg/m3for cooling room,609.88μg/m3for light-degree freezing room, and923.87μg/m3for freezing room, each concentration is more than the TVOC limit of indoor air quality standards600μg/m3. Reason for the high amount of aromatic hydrocarbon compounds in the refrigerator is that, all of the refrigerator materials release aromatic hydrocarbons compounds such as styrene, toluene, ethylbenzene and xylene in different degrees. The aromatic hydrocarbon compounds come from ABS liner, GPPS fruit and vegetable boxes, HIPS liner, HIPS masterbatch materials, especially HIPS and GPPS material; alkanes come from PVC door seal and other kinds of plastic; olefins come from ABS liner and polyurethane materials; oxygenated compounds and amines mainly come from PVC door seal and polyurethane materials; the special ingredients in refrigerator, such as acrylonitrile, amines and ethyl acetate, mainly come from the particular compounds that the refrigerator material release.3. Refrigerator odor composition affected by the storage of food, change of the odor composition in refrigerator in use is complex:the total amount of dimethyl disulfide, cyclopentane rise with time, the total content of styrene, ethanol and other components fall with time, in addition, there are many other trends with time. Refrigerator odor in use process comes mainly from a variety of foods stored in it, and different type of foods is in contribution to different refrigerator odors. In particular, pork impacts the changes of oxygenated compounds and alkane amines in the refrigerator, it is the main source material of amine odor; BTEX increases in rice is the main reason that the benzene substances rise in the refrigerator; tofu affects the changes of oxygenated compounds in the refrigerator, it releases high content of oxygenated compounds when in corruption time, and it is the main source material of amine odor; vegetables affect dimethyl disulfide, alcohols and amines changes, it is the major contributor and influencer to the refrigerator odor; watermelon is the main source material of the increase of styrene in refrigerator, and it affects the content changes of the alcohols, amines and others in the refrigerator.It determined the corruption extent of each food in storage through sensory and microbiological indicators. The results showed that, tofu in the first day, pork and watermelon in the third day, rice in the fourth day reached the fresh and critical point of corruption, during the critical time, refrigerator odor composition changed significantly. Sensory and microbiological indicators were both not accurate determinations for fresh and corruption of vegetables, but in the view of smell change, its impact on the refrigerator odor component change is significant.4. Opening the cooler door of the new bought refrigerator for ventilating for1.5h can achieve rapid odor eliminating in the refrigerator, but the effect is not lasting, it can return to the initial concentration two days later when closed the door. New refrigerator product can be deodorized quickly after heating2hours at80℃, and can not only reduce the customer’s senses unhappiness significantly, but also last longer time. Static activated carbon adsorption method can reduce the amount of odor substances in the refrigerator for50percent, but it requires one week time, therefore it’s fit for household in refrigerator odor deodorizing daily when the odor is not so serious. Cyclic activated carbon adsorption method can reached odor deodorant effect quickly, it takes50g activated carbon for40min cycle absorbing in power, hence, it’s fit for household in odor eliminating quickly in more serious condition. |
PDF Full Text Request