Preliminary Study on the Geochemical Characterization of Viticis Fructus Cuticular Waxes: From Latitudinal Variation to Origin Authentication

Abstract

Viticis Fructus (VF), a fruit known for its unique flavor profile and various health benefits, demonstrates substantial quality variations depending on its area of production. Traditional methods of production area verification based on internal compound analysis are hampered by a number of technical limitations. This investigation systematically characterized the cuticular wax composition of VF sample from a diverse variety of production areas. Quantitative analyses were conducted to evaluate the spatial distribution patterns of the wax constituents. Significant regional variations were observed: Anhui sample exhibited the highest total wax content (21.39 μg/cm²), with n-alkanes dominating at 76.67%. High-latitude regions showed elevated triterpenoid acid levels, with maslinic acid (0.53 μg/cm²) and ursolic acid (0.34 μg/cm²) concentrations exceeding those of their low-latitude counterparts by four- and three-fold, respectively. Altitudinal influence manifested in long-chain alcohol accumulation, as triacontanol reached 0.87 μg/cm² in high-altitude sample. Five key biomarkers demonstrated direct quality correlations: eicosanoic acid, n-triacontane, dotriacontanol, β-amyrin, and α-amyrin. This study established three novel origin identification protocols: single-component quantification, multi-component wax profiling, and wax ratio analysis. This work not only reveals the latitudinal dependence of VF wax composition, but also provides a scientific framework for geographical authentication. Our findings advance wax-based quality evaluation methodologies for fruit products, offering practical solutions for production area verification challenges in food raw materials.

Keywords: Viticis Fructus; biomarkers; cuticular waxes; origin authentication; origin identification.

Figure 1

Internal casticin content of VF collected in Hainan, Yunnan, Jiangxi, Zhejiang, Anhui, and Shandong Provinces (in the violin plot, the width of the violin represents the density of the data, thin lines indicate 95% confidence intervals, white bar-shaped regions indicate interquartile ranges, red dots indicate outliers, and white dots indicate means).

Figure 2

GC-MS chromatogram of VF wax (red represents fatty acids, green represents n-alkanes, blue represents primary alcohols, and purple represents triterpenoids).

Figure 3

(a) Wax content heat-map of VF cuticular waxes from different production areas (left side shows clustering groups). (b) Wax content heat-map of the four main categories of VF cuticular waxes from different production areas.

Figure 4

Schematic diagram of climate zones and altitudes from different VF production areas (the red patch indicates the area of the city where the production area is located).

Figure 5

Comparison of (a) hentriacontane, (b) n-tritriacontane, (c) n-pentatriacontane, (d) dotriacontane, and (e) n-tetratriacontane wax contents of VF from six production areas (HN, YN, JX, ZJ, AH and SD). Different lowercase letters indicate significant differences, p < 0.05, Duncan’s HSD test.

Figure 6

Comparison of (a) lignoceric acid, (b) hexacosanol, (c) maslinic acid, (d) beta-amyrin, (e) ursolic acid, and (f) triacontanoic acid wax contents of VF from six production areas (HN, YN, JX, ZJ, AH, and SD). Different lowercase letters indicate significant differences, p < 0.05, Duncan’s HSD test.

Figure 7

Comparison of (a) hexacosenoic acid, (b) octacosanoic acid, (c) triacontanol, (d) oleanolic acid, and (e) nonacosanoic acid wax contents of VF from six production areas (HN, YN, JX, ZJ, AH and SD). Different lowercase letters indicate significant differences, p < 0.05, Duncan’s HSD test.

Figure 8

Comparison of (a) hentriacontane, (b) n-tritriacontane, (c) n-pentatriacontane, (d) dotriacontane, (e) n-tetratriacontane, and (f) corosolic acid wax contents of VF from four production areas (HN, JX, ZJ and AH). Different lowercase letters indicate significant differences, p < 0.05, Duncan’s HSD test.

Figure 9

Fitting curves of (a) hentriacontane, (b) n-tritriacontane, (c) n-pentatriacontane, (d) dotriacontane, (e) n-tetratriacontane, and (f) corosolic acid waxes to latitude.

Figure 10

(a) Correlation heat-map of the content of five kinds of n-alkanes waxes with latitude. (b) PCA plot for all subsets of the five kinds of n-alkanes waxes.

Figure 11

Wax ratio of (a) hentriacontane/corosolic acid, (b) n-tritriacontane/corosolic acid, (c) n-pentatriacontane/corosolic acid, (d) dotriacontane/corosolic acid, and (e) n-tetratriacontane/corosolic acid. Different lowercase letters indicate significant differences, p < 0.05, Duncan’s HSD test.

Figure 12

Correlation heat-map between metabolites and cuticular wax of VF.

Figure 13

Optical photos of VF from various production areas, (a) HN, (b) YN, (c) JX, (d) ZJ, (e) AH, and (f) SD.