The peumo [Cryptocarya alba (Molina) Looser] is a Chilean Lauraceae tree with an endemic spread from Maule to the Araucania Regions. It is considered a threatened species in some areas of Chile, mainly due to overexploitation and habitat destruction [1]. Concerning its ecological importance, peumo is one of the representative species of the sclerophyllous forest of the central zone of Chile, including boldo (Peumus boldus), quillay (Quillaja saponaria), and hawthorn (Acacia caven) [2]. All sclerophyllous species are frequently used in low water consumption gardens. Likewise, quillay and boldo are species with interesting pharmacological and industrial applications of their compounds, being an important source of saponins [3] and boldine [4], respectively.

Despite no agro-industrial use, peumo leaves have been used in traditional medicine like infusion or ointment ^[2][5][2,5]. On the other hand, this tree has beautiful and pink-colored berries (Figure 1), called peumos, collected and consumed by the Mapuche Amerindians, principally as a cold infusion, since pre-Colombian times. This fruit is composed of edible and pink skin, with intense flavor and aroma at maturity, and a large seed like a nut; these characteristics have allowed its gastronomic use in recent years [2].

The essential oil of this species was reported to be composed mainly of 1-terpinen-4-ol and p-cimol [6], while the cryptofolione derivative has been the only compound isolated from the edible fruits [7]. Domínguez and Martínez (2002) [8] reported that the peumo fruit skin has many polyphenols, but it is unclear if this potential is linked to a particular genotype. Simirgiotis (2013) [9] reported a high antioxidant capacity (9.12 ± 0.01 mg·mL⁻¹), determined by DPPH assay in ripe fruit and flavonoid glycosides, phenolic acids, anthocyanins, and flavonoid aglycons as the major phenolic compounds in fruit and aerial parts of peumo extracts.

The antioxidant capacity of native Chilean fruits like murtilla (Ugni molinae Turcz.) (10,770 ± 453), maqui (Aristotelia chilensis (Molina) Stuntz) (19,850 ± 966), and calafate (Berberis sp.) (25,662 ± 3322), determined by oxygen radical absorbance capacity (ORAC: μmol TE/100 g fresh weight), has been described as higher than commercial berries such as raspberries (6903 ± 1019), blueberries (8869 ± 334), and blackberries (9043 ± 1253) [10]. Furthermore, this antioxidant capacity has been associated with a high functional potential ^[10][11][12][10,11,12]. Likewise, water-soluble extracts of maqui berry have been reported to prevent the oxidation of copper-induced low-density lipoprotein (LDL), adipogenesis, and inflammatory actions, and to protect human endothelial cell cultures ^{[12][13][14][15][16]}[12,13,14,15,16].

The quality, physiological parameters, and potential health benefits of many attractive native fruits could be affected by inadequate handling postharvest. Therefore, knowledge about the fruit’s physiological and physicochemical parameters before studying the healthy potential of native fruit is relevant.

The present study classified three developmental stages of peumo (C. alba) fruits (Figure 1). A constant boost in fruit fresh and dry weights was registered according to ripening during the first harvest season, and non-significant differences between Ca2 and Ca3 stages were observed during the second season (Table 1). The water activity displays non-significant differences during ripening, with a similar decrease throughout both seasons. The fruit length increased during both seasons, while the diameter only increased for the 2017 season; despite the above, the fruits have a thin shape in all analyzed stages and both seasons (Figure 1, Table 1). The fruit firmness displays a constant reduction during ripening in both seasons, with firmness in ripe fruit near 5 N (Table 1).

Determinations of total antioxidant capacity by four different methods (FRAP, TEAC, DPPH, and ORAC assays) indicated that the increase in antioxidant capacity, according to the ripening progress, displayed significant differences between the Ca1 and Ca3 stages. This trend was similar to those observed for total polyphenols content (TPC) and total flavonoids content (TFC) (Table 2). However, no differences were observed in the ORAC method for the second season. The TPC in ripe peumo was near 17 mg GA/g FW, and TFC was near 9 mg QE/g FW in both seasons; these values were higher than those determined for ripe blueberries in the 2018 season (TPC:2.75 mg GA/g FW and TFC: 2.12 mg QE/g FW).

The principal component analysis (PCA) of antioxidant capacity for the 2017 (Figure A1A) and 2018 (Figure A1B) harvest seasons describes a similar behavior for FRAP, TFC, and TEAC analysis. However, DPPH and TPC have different behavior for each season, with a high correlation with the other antioxidant variables in the 2017 season and a mainly orthogonal location (not correlated) for 2018 season. The correlation between antioxidant analysis for the 2017 (Table A1) harvest season describes a significant correlation, where FRAP, TEAC, and TFC are the most correlated. Nevertheless, we have a different correlation for the 2018 (Table A2) season, where TPC and DPPH describe not correlated behavior. However, FRAP, TEAC, and TFC still present a positive correlation between them in the season.

The chemical composition of peumo fruit extract was determined by non-target analysis using U-HPLC/MS LTQ in both positive and negative modes (Figure 2). Identified compounds (Table 3) included many flavonoids, alkaloids, and lignins. The main part of flavonoids was represented by quercetin and its derivatives and metabolites, followed by proanthocyanidins (namely procyanidins), phenols (catechin and epicatechin) and polyphenols (chlorogenic acid and its analogue, 4-caffeoylquinic acid), flavones (luteolin 7-O-glucuronide, sexangularetin), and other flavonoids. Lignans were represented by 4-O-methylcedrusin and (+)-lariciresinol. Alkaloids were represented by cryprochine and its stereoisomer. The high content of flavonoids could be responsible for the antioxidant and anti-inflammatory activity of peumo extract. Also, the ORAC value of peumo extract (500 mg/mL) was 0.637 ± 0.061 mmol/g DW (Table 3).

The pH range during the development of peumo fruits was 5.6–6.3. Titratable acidity (TA) could not be determined, as no drastic changes were detected in the titration curve. A significant soluble solids content (SSC) increase was observed only for the 2017 season from the Ca1 to Ca2 stages, with an SSC of 24–38° Brix in ripe peumo fruit (Table 1).

Concerning color changes during fruit development of the peumo (Table 1), the hue angle (h°) displayed a significant decrease during ripening in both seasons. In contrast, the L* and b* decreased significantly only in the second season. A higher increase of a* in the ripe stage was observed in the 2018 season. Nevertheless, the instrumental color obtained suggests the increase in red color during peumo ripening; the obtained data were not precise according to the visual color (Figure 1).

In the present study, the CO₂ production of fruits decreases continually until the end of ripening during both seasons (Table 1). Indeed, ethylene production was not detected at any stage of peumo fruits (Table 1) in both seasons, suggesting a fruit’s non-climacteric behavior.