Changes in the chemical composition of basil caused by different drying procedures.
Basil (Ocimum basilicum L.) leaves were dried using a microwave oven at atmospheric pressure or two traditional methods: air-drying at 50 degrees C and freeze-drying. The microwave-drying was carried out at different powers and times on raw basil leaves, while for air and freeze-drying techniques, both raw and blanched leaves were used. The raw and dried basil was analyzed for selected aroma compounds by gas chromatography/mass spectrometry-selected-ion-monitoring, the chlorophyll a and b by HPLC and the color by a reflected-light colorimeter. For dried samples microwaved for 1 min at 270, 2 min at 440, 1 min at 650, and 1 min at 1100 W, the percentage retentions of the characteristic volatile compounds (eucalyptol, linalool, eugenol, and methyl eugenol) were higher than in the samples dried by traditional methods, with the exception of freeze-dried unblenched basil. Microwave drying allowed a larger retention of chlorophyll pigments than air-drying and freeze-drying (with or without blanching) and preserved the color of the raw basil. Microwave drying requires a much shorter treatment and implied the simultaneous blanching of the material.
Di Cesare
Luigi Francesco
LF
IVTPA, Via G. Venezian 26, 20133 Milan, Italy. dicesare.ivtpa@interbusiness.it
Forni
Elisabetta
E
Viscardi
Daniela
D
Nani
Renato Carlo
RC
D002734:Chlorophyll / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D003890:Desiccation / Q000379:methods*; D005511:Food Handling / Q000379:methods*; D005612:Freeze Drying; D008401:Gas Chromatography-Mass Spectrometry; D006358:Hot Temperature; D008872:Microwaves; D018649:Ocimum basilicum / Q000737:chemistry*; D010858:Pigmentation; D018515:Plant Leaves; D014835:Volatilization
D002734:Chlorophyll