Nutritional Value and Polyphenolic Compounds with Antioxidant Capacity in Plinia peruviana Berries from the Biodiversity of Emboscada, Paraguay ^†

Abstract

The Plinia genus comprises an underestimated group of fruit trees native to the neotropics of South and Central America. One such species is Plinia peruviana (Poir.) Govaerts, commonly known as ‘Yvapurú’, which belongs to the Myrtaceae family. Its fruits have high nutraceutical potential and are used in the food and medicinal industries. However, scientific information on its composition and bioactive properties remains limited at the regional level. This study aimed to determine the nutritional composition and antioxidant potential of wild P. peruviana fruits collected in a native forest in Emboscada, Paraguay. Official AOAC methods were employed to analyse the centesimal composition, and the vitamin C content, Total Phenolics Compounds (TPC), and total monomeric anthocyanin (TMA) content were determined in freeze-dried pulp and peel. The main components of whole fruits were total carbohydrates and dietary fibre (12.2 ± 0.7 g/100 g and 9.9 ± 0.8 g/100 g, respectively). The main minerals present were potassium (252 ± 9 mg/100 g), sodium (49 ± 3 mg/100 g), magnesium (46 ± 5 mg/100 g), calcium (21.5 ± 1 mg/100 g) and phosphorus (4.1 ± 0.9 mg/100 g). In terms of antioxidant potential, the peel exhibited higher concentrations of total phenolic compounds (730 ± 5 mg EAG/100 g) and anthocyanins (191 ± 15 mg C3G/100 g) than the pulp (611 ± 13 mg EAG/100 g). These results confirm that P. peruviana fruits have a valuable nutritional profile, providing significant amounts of dietary fibre and essential minerals, as well as high levels of bioactive compounds associated with antioxidant capacity. Using them as a functional food could help prevent chronic diseases and strengthen food security. The study also expands knowledge of Paraguay’s fruit biodiversity and supports the sustainable utilisation of underutilised native species.

1. Introduction

Latin America and the Caribbean are home to a wide variety of fruits that are highly nutritious and bioactive [1]. As well as being consumed traditionally, these species are used in folk medicine and in diets that promote well-being and reduce the risk of chronic diseases. Phytochemical characterisation enables their revaluation and the creation of new economic opportunities. In recent years, demand for functional ingredients has grown due to consumer concerns about obesity, diabetes and hypertension [2]. In this context, Plinia peruviana (Poir.) Govaerts, commonly known as ‘Yvapurú’, is a native fruit of the Myrtaceae family with great potential. It produces purple-to-black berries with white pulp and a sweet-and-sour taste when ripe [3]. Nutritionally, it is low in carbohydrates and suitable for glycaemic restriction diets [4], providing fibre at levels that comply with the Mercosur Technical Regulation [5]. In terms of minerals, it is notable for its higher potassium, magnesium, phosphorus and sodium content than related species such as P. cauliflora and P. jaboticaba [6]. Bioactive compounds are also important: the pulp is rich in vitamin C, while the peel contains high concentrations of polyphenols and anthocyanins, which have antioxidant, anti-inflammatory and anti-diabetic properties [7]. Furthermore, comprehensive utilisation of the fruit promotes circular economy models (food upcycling) by adding value to nutrient and phytochemical-rich by-products, thereby contributing to sustainability and the Sustainable Development Goals [8]. This study aimed to evaluate the nutritional and antioxidant content of wild Plinia peruviana fruits from Emboscada, Paraguay’s biodiversity hotspot.

2. Materials and Methods

2.1. Plant Material and Sampling

Ripe fruits of Plinia peruviana were collected from a native forest in the locality of Emboscada, in the territory of Cabaña Itapé, Cordillera Department, in the eastern region of Paraguay. Sampling was performed manually by random sampling of the trees. Ripe wild fruits were identified by their intense purple colour. Approximately 50 kg of fruit were collected. The total quantity was divided into successive quarters to obtain a single representative sample (dividing the fruits into four equal parts, separating two of them and then mixing them again to reduce the original sample size by half). The fruits were sent refrigerated for the pertinent analyses. Once there, the fruit samples were homogenised in an electric grinder to determine the macronutrient, micronutrient and dietary fibre content. The remaining quantity of fruits were separated into peel and pulp, which were then homogenised and freeze-dried separately. Freeze-dried samples were analysed for total anthocyanin and phenol content [9].

2.2. Analysis

For the centesimal composition, the Official AOAC 2000 methods were used to determine the levels of lipids, protein, dietary fibre, and minerals and total carbohydrate content. Total phenols were determined using the Folin–Ciocalteu method. Total monomeric anthocyanins were determined by high-performance liquid chromatography (HPLC). Both the extraction of anthocyanins from the skin and pulp, and subsequent determination, were carried out in accordance with the agreed method for determining anthocyanins in native fruits, as set out in the ‘Standardised Protocols for the Valuation of Native Fruits of the PROCISUR’ [3,10].

3. Results and Discussion

3.1. Centesimal Composition and Minerals

The whole fruits had a high moisture content of 79.3 ± 0.2 g/100 g (see

Table 1. Composition of whole P. peruviana fruits.

Centesimal Composition (g/100 g Fresh Fruit)
Parameters	Media ± SD
Moisture	79.3 ± 0.2
Total available carbohydrates	12.2 ± 0.7
Dietary Fibre	9.9 ± 0.8
Total protein	0.80 ± 0.06
Total lipids	0.06 ± 0.01
Ash	0.57 ± 0.02
Minerals (mg/100 g SMTC)
K	252 ± 9
Mg	47 ± 5
Na	50 ± 3
P	21 ± 1
Ca	4 ± 0.9
Fe	2.6 ± 0.2
Zn	2.8 ± 0.001
Mn	0.8 ± 0.02
Cu	0.21 ± 0.02

The results are shown as average values with their corresponding standard deviations. n = 3.

for the results). These data are below the values described by Seraglio et al. [11] in Myrciaria cauliflora (85.6%). This high-water content limits the shelf life after harvest, highlighting the need for conservation strategies. Total carbohydrate content was similar to the values reported by Schultz et al. for Myrciaria spp. (13.7–13.8 g/100 g) [1]. From a nutritional point of view, this profile makes the fruits suitable for people with carbohydrate consumption restrictions when considered alongside the recommendations of the American Diabetes Association (ADA) [4]. By contrast, the dietary fibre content was higher than that reported by Schultz et al. [1] for M. cauliflora (3.5 g/100 g), which is a significant amount in relation to the 25–30 g/day recommended by the Mercosur Technical Regulation (2018). In terms of minerals, the major component was potassium, followed by sodium, magnesium, phosphorus, and calcium [5]. These results show higher values than those by Leterme et al. [6] for P. cauliflora and M. cauliflora, except for calcium. This variability could be attributed to genetic factors and the harvesting agroecological conditions [6,12]. The identified macrominerals play critical roles in human health as structural components and enzyme cofactors, which reinforces the functional value of these native fruits as a natural source of essential micronutrients [11].

3.2. Total Polyphenols and Total Monomeric Anthocyanins

Antioxidant compounds, including vitamin C, total polyphenols (TPC), and Total monomeric anthocyanins (TMAs), were evaluated in the peel and seed pulp fractions of the freeze-dried samples. The vitamin C content was higher in the seeded pulp than in the peel (seeded pulp: 9.6 ± 0.7 mg/100 g and peel: 8 ± 1 mg/100 g), respectively (

Table 2. Antioxidant potential in the peel and pulp with seeds of Plinia peruviana.

Parameter	Peel	Pulp + Seeds
Vitamin C (mg/100 g)	8 ± 1 a	9.6 ± 0.7 b
Total Phenolic Compounds (mg EAG/100 g)	730 ± 5 a	611 ± 13 b
Total monomeric anthocyanins (mgC3G/100 g)	191 ± 15 a	3.6 ± 0.3 b

Values expressed as mean ± standard deviation. Different superscript letters indicate significant difference by Student’s t-test with 95% CI, p < 0.05 between peel and pulp with seeds, where mg EAG/100 g = milligrams of gallic acid equivalent per 100 g of fresh sample.

). The total vitamin C content in P. peruviana fruits in peel and pulp was 17.3 mg/100 g, higher than that reported for blueberries (9.7 mg/100 g of fruit) or Rubus hassleri fruits (9.8 mg/100 g) and lower than that of blackberries (21 mg/100 g of fruit). The content of vitamin C, TPC, and TMA in the peel and pulp with seeds was a fraction of that in the freeze-dried samples. The vitamin C content is higher in pulp with seeds than in the peel (pulp with seeds: 9.6 ± 0.7 mg/100 g and peel: 8 ± mg/100 g), respectively (Table 2). The total vitamin C content in the fruits of P. peruviana in peel + pulp was 17.3 mg/100 g, higher than that reported in blueberries (9.7 mg/100 g of fruit) or Rubus hassleri fruits (9.8 mg/100 g) and lower than that in blackberries (21 mg/100 g of fruit) [13].

The TPC observed in the peel (730 ± 5 mgEAG/100 g) was significantly higher than that found in the pulp with seeds (611 mg EAG/100 g ± 13), which is to be expected given the colour and astringent taste characteristics due to the tannin content in the peel. When compared to other fruits recognised for their antioxidant activity, P. peruviana fruits provide higher amounts of TPC than fruits such as açaí, blackberry, blueberry, raspberry and strawberry, which provide between 607–708; 198–2349; 101–324; 135–2494; and 221–293, respectively [12]. Consequently, the TPC content in the peel and pulp of P. peruviana suggests its great potential as a source of these antioxidant-capable compounds. The TMA content was significantly higher in the peel (191 ± 15 mg C3G/100 g) than in the Pulp + seeds (3.6 ± 0.3 mg C3G/100 g). Our results for the peel are higher than those reported by Almeida et al. [9] for Myricaria cauliflora. They are also comparable to fruits recognised for their antioxidant capacity, such as açaí, blackberries, grapes and strawberries [9]. However, P. peruviana contains higher levels of bioactive phenolic compounds, making it a relevant source. Variability between studies reflects environmental, genotypic, and processing differences. Notably, the year in which the fruits were collected for this study was characterised by dry conditions which may have impacted their secondary metabolism. Similarly, genetic variability among individuals of the same species is a key factor that has not yet been thoroughly explored in local literature. This creates opportunities for future studies to focus on genetic characterisation, ecosystem sustainability, and selecting genotypes with better bioactive properties and agricultural potential.

4. Conclusions

The fruits of Plinia peruviana from Paraguay are a good source of dietary fibre and contain low levels of carbohydrates, making them suitable for diets that restrict glycaemic index. They are notable for their mineral content, particularly their high levels of potassium, magnesium, phosphorus, and sodium, which confirms their potential as a source of essential micronutrients. In terms of bioactive compounds, the peel has a high total phenol and anthocyanin content, while the pulp is a good source of vitamin C. Compared to other fruits recognised for their antioxidant capacity, P. peruviana has competitive or superior values, which reinforces its value as a functional food. These variations reflect the influence of genetic and environmental factors, opening up opportunities for selecting and managing genotypes with greater nutritional and antioxidant potential.