Authentication and quality evaluation of not from concentrate and from concentrate orange juice by HS-SPME-GC-MS coupled with chemometrics

Abstract

Substituting of not from concentrate (NFC) orange juice with from concentrate (FC) orange juice is a novel adulteration problem. This study used headspace solid-phase microextraction-gas chromatography-mass spectrometry coupled with chemometrics to discriminate between NFC and FC orange juices. Twenty-five compounds were identified as differential compounds for NFC and FC orange juice discrimination. During processing, concentration treatment is a key step for forming differential compounds. After the treatment, 25 differential compounds decreased significantly. Among, trans-isopiperitenol (5.45 ± 0.79 μg/L), ethyl butanoate (106.5 ± 7.24 μg/L), butyl butanoate (3.60 ± 0.19 μg/L), hexyl butanoate (2.82 ± 0.14 μg/L), ethyl octanoate (5.04 ± 0.39 μg/L), 1,3,8-p-menthatriene (4.97 ± 0.49 μg/L), p-mentha-1,5,8-triene (4.82 ± 0.59 μg/L), and limona ketone (5.00 ± 0.53 μg/L) declined until they were undetectable. These 25 differential compounds can discriminate NFC and FC orange juices processed by thermal concentration and other sterilization methods. Based on the 25 differential compounds, a partial least squares discriminant analysis model was constructed to identify commercial samples. 100% NFC and 86.67% FC commercial orange juices were consistent with their labels. These results clarify the volatile differences in volatile compounds and their causes for NFC and FC orange juices and provide references for juice quality control.