Elucidation of aroma compounds in passion fruit (Passiflora alata Ait) using a molecular sensory approach

Abstract

In this experiment, Guangxi passion fruit was used as the raw material for natural aroma extraction using the spinning cone column (Spinning Cone Column, SCC) technique. In combination with the semi-quantitative method, the aroma characteristics of the raw pulp (raw whole-fruit puree, PU) before SCC processing, residue (Residue, RS) and extract (Extract, EX) after SCC processing, and passion fruit juice (Juice, JU) were evaluated for their aroma characteristics using headspace gas chromatography-mass spectrometry (HS-SPME-GC-MS), gas chromatography-ion mobility spectrometry (GC-IMS), electronic nose, and sensory evaluation. As a result, a total of 110 aroma substances were detected in four samples, and 33, 38, 73, and 28 aroma components were detected from PU, RS, EX, and JU, respectively. There are 50 compounds in EX with concentrations greater than 10 μg/kg, and 19 of them had OAV values greater than 1, including β-Ionone and linalool, which contributed significantly to the aroma. The aroma profiles and characteristics were further analyzed for JU and EX using the e-nose sensor, and it was found that both showed similar aroma profiles. The sensory evaluation results were also in general agreement with the results obtained from the electronic nose, with EX having mainly "floral", "fruity," and "sweet" aromas. The results demonstrated that the spinning cone column technique can increase the fresh and natural fruity aroma of passion fruit in the extract, which has the effect of enriching the aroma and improving the aftertaste. This study will make a foundation for passion fruit SCC extract application in drinks. PRACTICAL APPLICATIONS: Compared with traditional extraction technology, spinning cone column technology has the advantages of high mass transfer efficiency, short extraction time, a wide range of temperature control, and the most complete extracted flavor substances, which greatly reduces the damage degree of heat-sensitive flavor substances and condense aroma. It is widely used in beverages, wine, dairy products, fruit and vegetable, spice essential oil, and other industries. Passion fruit flavor prepared by SCC technology has the advantages of high purity and high concentration, which can be used in solid drinks, baked food, convenience food, tobacco, perfume, and other products. Besides, GC-IMS is an efficient and rapid new analytical technique, which has been widely used in the flavor analysis of volatile organic compounds in food and traditional Chinese medicine samples.

Keywords: gas chromatography-ion mobility spectrometry (GC-IMS); gas chromatography-mass spectrometry(GC-MS); odor activity values; passion fruit; spinning cone column; volatile components.