Refinery And Application Of Pyroligneous Acids From Bitter Almond Shell

Pyroligneous acids were prepared throngh pyrolyzing bitter almond shell, then refinedand treated by reduced pressure distillation to respectively get refined pyroligneous (M), oncereduced-pressure distillation pyroligneous (M1), twice reduced-pressure distillationpyroligneous (M2), the basic property of the pyroligneous acids were analyzed. M, M1, M2were dehydrated through diethyl ether to respectively get dehydrated pyroligneous acids MP,MP1and MP2. Antioxidant activity of them were tested. Chemical components of MP andMP2were analyzed with GC-MS. Antimicrobial activity and antibacterial stability as well asminimal inhibitory concentration (MIC) of MP2were also tested. MP2as a preservativeefficacy was evaluated through microbial challenge test and sensory evaluation. The resultsare reported as follows.1. The colours and smells of MP1, MP2were weaker, and the contents of phenols andacids of MP1, MP2had phased down compared with MP, MP, MP1and MP2had antioxidantactivity and existed a significant effect relationship in an order of MP>MP1>MP2, whichpresumedly were correlated with the contents of phenols and acids.2. The antimicrobial activity results indicated that all these microorganisms wereeffectively inhibited by MP2and the anti-mould activity was better than the antibacterialactivity. The antibacterial effect of MP2on each bacterium or fungus was relatively significant.The antimicrobial activity increased with the concentration, and antibacterial effects of MP2on these bacteria in an order of Bacillus subtilis> Pseudomonas aeruginosa> Staphylococusaureus Rosenbach> Clostridium perfringens> Escherichia coli. The toxicity determinationof MP2showed it had better controlling effects to fungus, its EC50was in an order ofPhanerochaete chrysosporium> Rhizopus oryzae> Mucor racemosus> Cochliobolussativus> Poria plaoenta> Botrytis cinerea> Aspergillus niger.3. The minimal inhibitory concentration(MIC) of MP2on S. aureus and E. coli as well astheir survival curve and mortality curve at different concentrations were accurately calculatedthrough decimal reduction time method. The MIC of pyroligneous acid to S. aureus and E.coli respectively were0.44%and0.46%, it showed pyroligneous acid has strongbacteriostatic activities to both typical bacteria. The stability to temperature, acid, alkali, ultraviolet, activated carbon and microwave of pyroligneous acid were also studied. The resultshowed that it was very stable to the treatments above, which presented pyroligneous acid hasgood antibacterial stability.4. Chemical components of MP and MP2were analyzed with GC-MS. Totally23compounds were identified from MP, accounting for95.46%of the total peak area. Organicacids, phenols and ketones in MP accounted for74.73%、10.92%and6.77%, respectively.Other content accounted for3.04%. The highest content components was acetic acid,accounted for70.83%of the total. Twenty five compounds were identified from MP2whichaccounted for93.45%of the total peak area. The main composition of MP2was organic acids(59.39%), phenols (18.38%) and ketones (7.71%). Acetic acid (50.71%) was in the highestcontent in MP2. High antimicrobial activity of bitter almond shell pyroligneous acid might berelated to its high contents of organic acids compounds.5. Using homemade emulsion contained no extra preservatives, which were divided into7groups, among the first4groups,2%,3%,4%,5%MP2were added respectively, the fifthgroup was used as blank control,0.2%commercially available antibacterial agent was addedin the sixth group as positive control,1%MP2and0.1%commercially available antibacterialagent with a ratio of1:1were added the the seventh group as compounded group.Antimicrobial activity of above seven groups were studied through the artificial addedbacterium once (28days) and three times (42days) of microbial challenge test (bacteria andmoulds) methods. The results showed the evaluation of two microbial challenge test methodswere basically the same. The antimicrobial activity of the six kinds of anti-corrosion systemsexisted a roughly effect relationship in an order of0.2%>1%+0.1%>5%>2%>4%>3%>2%, the systems4%,5%,0.2%and1%+0.1%passed the test; The six kinds ofanti-corrosion systems for mold inhibitory effects were good, all groups except blank controlgroup passed the two methods of microbial challenge test of mould.6. Emulsion sample (added5%MP2as a cosmetics antiseptic) was evaluated throughsensory evaluation. The results showed that the key indicators (color, texture, spreadability,moisture and glossiness) of the sample is "optimal", which were in consistentence with thecommercial emulsion, while the indicators of viscous feeling and smell were worse thenpositive control group, that has yet to be improved.