Study of Volatiles from ‘Pera’ Sweet Orange Peel Using Karl Fischer Titration, GC-FID and GC/MS Techniques

• Main Authors: K. Zanella, C.L. Pinheiro, E. Tomaz, O.P. Taranto
• Format: Article
• Language: English
• Published: AIDIC Servizi S.r.l. 2013-06-01
• Series: Chemical Engineering Transactions
• Online Access: https://www.cetjournal.it/index.php/cet/article/view/6463

Orange is a large cultivated fruit and worldwide studied. During its industrial processing it is obtained juice and essential oil as the main products and, d-limonene, pectin and citrus pulp as by-products, where the last one is dried, stored and commercialized. However, during the drying process, volatile organic compounds (VOCs) present in the orange peel (albedo and flavedo), are issued and released to become atmospheric pollutants, causing environment problems related to the formation of tropospheric ozone, photochemical smog, olfactory discomfort of local residents. Thus, this work aims: determine the moisture content from albedo and flavedo from ‘pera’ sweet orange (Citrus sinensis L. Osbeck), as well as, quantify and qualify the VOCs released during the drying process. For that, the following steps were taken: (1) determination of water and volatile contents via oven dryer at 378 K for 24 hours; (2) determination of water content via Karl Fischer titration at 378 K and nitrogen output at 90 mL/min; (3) determination of volatile content by the difference between (1) and (2); (4) collect and make the qualitative and quantitative analysis of volatile compounds by gas chromatography coupled to mass spectrometry (GC/MS) and by gas chromatography with flame ionization detector (GC-FID), by using the response factor. The results shown that, in wet basis, the water content and the volatiles content were 66 % and 11 % for the albedo and 67 % and 6 % for the flavedo, respectively. In addition, the volatile organic compounds identified were 2-methylene-1,4-dioxane, a-pinene, 3-carene and d-limonene and the VOCs quantified were a-pinene, 3- carene and d-limonene, both of albedo as flavedo. So, we conclude that the methodology adopted in this work is adequate to determine the volatile organic compounds released during the drying of orange peel, as well as qualify each chemical compound among the volatiles.