Italian watermelon, biodiversity and health

Thewatermelon, often considered as a simple  summer fruit, actually reveals a rich cultural heritage, historical and  nutritional. This article explores its millennial origins, the spread in Italy, and the regional excellences, from protected varieties like theAnguria Reggiana IGP to local rarities such as the one from Gonnosfanadiga (Sardinia).

A special focus is dedicated to  Health benefits, supported by recent scientific studies, highlighting the role of  lycopene e citrulline in wellness  cardiovascular and muscle recovery. Completing the picture, tips for purchasing and kitchen ideas to enhance a fruit symbolizing a healthy and  sustainable.

Italian watermelon, between history and legends

The watermelon (Citrullus lanatus), also known as  watermelon, has  African origins and a millennial history intertwining tradition, agricultural innovation, and scientific research. Cultivated already inancient Egypt, as evidenced by seeds and frescoes found in pharaonic tombs, it spread in  the Mediterranean basin and subsequently in Roman and Byzantine Italy.

In the medieval period, known by the names citrullus e pepone, found space in  monastic gardens where it was kept as a precious resource.

A  Emilian legend tells that the watermelon of  Novellara was born from a seed brought by a pilgrim returning from the Holy Land, later becoming a symbol of Reggio Emilia's agricultural excellence. This tradition was confirmed in the  Renaissance documents from the 16th century, when correspondence between the Padane courts already praised the extraordinary quality of watermelons grown in these  fertile lands.

Botanical characterization and seasonality

Watermelon belongs to the family of  Cucurbitaceae and it is an annual plant characterized by trailing and hairy stems, lobed leaves, and unisexual yellow flowers. The fruit, technically a  peponide, typically has red pulp, sometimes yellow in specific varieties, and numerous  seeds which vary from black to white depending on the  cultivar.

From a nutritional point of view, watermelon stands out for itshigh water content (over 95%) and the  low caloric density, characteristics that make it ideal forhydration and weight control. The  seasonality naturally extends from June to September, with the possibility of early harvest in May through  protected cultivation which use tunnels and greenhouses to extend the production period.

Italian watermelons,  terroirs and excellences

Italy hosts several  terroirs dedicated to watermelon cultivation, each with characteristics  pedoclimatic unique that confer specific  organoleptic properties to the fruits.

The Reggiana Watermelon PGI represents the only watermelon with aprotected geographical indication. Cultivated in  Lower Reggiana, between the provinces of Reggio Emilia and Mantua, it benefits from calcareous and clayey soils particularly rich in  potassium. The disciplinary regulations provides for three varieties: Ashai Mijako (round shape), Crimson (oval) and Sentinel (elongated), with weights ranging from 5 to 20 kilograms. The peculiarity of this product lies in the  sugar content above 11° Brix for the Ashai Mijako variety, conferred precisely by the mineral composition of the soils.

The  Po Delta, between the provinces of Ferrara and Rovigo, exploits  sandy soils and a humid microclimate influenced by the proximity of the Adriatic Sea. Here, a integrated cultivation with drip irrigation and three-year rotations that preserve soil fertility. The  controlled salinity of the soils and the high availability of potassium create ideal conditions for the development of particularly  Sweets and intensely flavored.

The Mantuan and Reggiana boast  historic cultivations that integrate perfectly into rotations with cereals and forage crops. The  local varieties, selected over the centuries, are harvested strictly by hand using the traditional billhook. There Black Pearl of Mantua, with its characteristic dark skin and seedlessness, represents an example of  biodiversity preserved through traditional peasant knowledge.

In Apulia, in the areas of Bari and Foggia, the production of  early watermelons, often grown in tunnels to anticipate marketing. The  Apulian varieties are characterized by adaptation to  southern climates and by  resistance to high temperatures, maintaining excellent organoleptic qualities even in extreme climatic conditions.

Sardinia preserves a  genetic heritage unique with thewatermelon of Gonnosfanadiga, recognized as Traditional Agri-food Product by the Ministry of Agriculture. This  native variety, locally called ‘Call’e boi’ for its elongated shape resembling the bovine rumen, features an intense dark red color and a distinctive sweet flavor. Cultivated according to  semi-extensive practices with five-year rotations, it benefits from soils at the foot of Monte Linas which confer unique organoleptic characteristics. Sowing is done only with seeds selected from the best fruits, maintaining a distance of at least two kilometers from other varieties to avoid  genetic contaminations.

Nutritional values

The official nutritional data of the  CREA (Food and Nutrition Research Center) highlight the excellent nutritional profile of the watermelon. In 100 grams of fresh product, there are only  16 Kcal (67 kJ), with a composition featuring  95.3% water, 3.7 grams of carbohydrates (entirely available as  soluble sugars), 0.4 grams of proteins and 0.2 grams of  fibers, mostly insoluble type.

The mineral content stands out for the high presence of  potassium – 280 mg/100g, equal to 14% of the Nutrient Reference Values (Nutrient Reference Values, NRVs) indicated in Annex XIII to the  Food Information Regulation (EU) 1169/11 – which, it is reminded, is fundamental for theelectrolyte balance and the  muscle function. Calcium, phosphorus and iron are instead present in minimal quantities (7, 2 and 0.2 mg/100g respectively).

As for vitamins, the watermelon provides  8 mg/100g of  vitamin C, equal to 10% of the Nutrient Reference Values. The presence – although modest (37 μg/100g) – of vitamin A (retinol equivalent) mainly derives from the  carotenoids, with a particular concentration of lycopene. The  B group vitamins are then present in small amounts: thiamine (B1) and riboflavin (B2) 0.02 mg/100g each, niacin in traces.

Health benefits

The  scientific research has consolidated and deepened the understanding of the health benefits associated with watermelon consumption, identifying the  mechanisms of action specific and the  therapeutic applications potential:

• lycopene and cardiovascular health. Watermelon contains the highest concentration of bioavailable lycopene among all fresh fruits, with values exceeding those of tomatoes. Recent studies have shown that watermelon lycopene, thanks to the aqueous matrix, presents a  higher bioavailability of 15-20% compared to other plant sources (Edwards et al., 2003). A  meta-analysis of 21 clinical studies conducted on over 900 patients highlighted that a daily intake of 2-20 mg of lycopene can significantly reduce the  risk of cardiovascular diseases through the reduction of LDL oxidation and improvement of endothelial function (Przybylska & Tokarczyk, 2022);

• citrulline and blood pressure control. The  citrulline, a non-essential amino acid particularly concentrated in the white part between pulp and rind, has shown promising effects on cardiovascular health. A  randomized controlled study demonstrated that supplementation with watermelon extract containing 4 grams of L-citrulline for 6 weeks improved  vasodilation and reduced blood pressure in pre-hypertensive subjects, significantly (Figueroa et al., 2012). A recent meta-analysis of 8 randomized controlled trials confirmed that doses of 3-9 grams of citrulline per day can reduce systolic pressure by an average of 4.1 mmHg, with stronger effects using at least 6 grams daily (Alshahrani et al., 2023). The  mechanism of action of citrulline is based on its renal conversion into arginine, precursor ofnitric oxide (NO). Increased NO bioavailability promotes vasodilation, improves endothelial function, and reduces arterial stiffness, benefits particularly evident during induced cardiovascular stress (Figueroa et al., 2014);

• antioxidant and anti-inflammatory properties. Recent studies have deepened thesynergistic action of  bioactive compounds of watermelon (Bin-Jumah et al., 2022; Burton-Freeman et al., 2021). The fresh juice contains 16.94-20.23 mg/100ml of polyphenols (gallic acid equivalents), with a particular concentration of flavonoids and phenolic acids. The antioxidant action is enhanced by the simultaneous presence of vitamin C, beta-carotene and lycopene, creating a  synergistic effect in the neutralization of  free radicals;

• support for muscle recovery. Allerton and colleagues (2018) highlighted the role of citrulline in improving the  sports performance and the  post-exercise recovery. A systematic review demonstrated that supplementation with citrulline for at least 7 days significantly improves  performance aerobic performance through increased production of  nitric oxide, facilitating themuscle oxygenation and reducing the accumulation of fatigue metabolites;

• potential neuroprotective effects. Emerging research also suggests that lycopene may exert  neuroprotective effects. Studies on animal models have shown that dietary supplementation with watermelon extract rich in lycopene improves  cognitive functions, reducing oxidative stress and tau protein hyperphosphorylation, typical features of  Alzheimer’s disease (Chen et al., 2015).

Uses in cooking and gastronomic enhancement

Watermelon offers  culinary versatility that goes far beyond fresh consumption. In  Sicily, it is the basis for the traditional ‘melon gelo’, while in Emilia-Romagna it is traditionally accompanied with  Pan de Re Reggiano, made with ancient grains and sourdough. Modern preparations include  summer salads with feta, arugula and cucumber, highlighting the contrast between the sweetness of the pulp and the strong flavor of the other ingredients.

The transformation into  juices e smoothies keeps the nutritional properties unchanged, while the preparation of  sorbets and granitas represents a healthy way to enjoy low-calorie summer desserts. The  artisan preserves of peel, rich in natural pectins, constitute a full valorization of the fruit, while the  semi tostati, traditionally consumed in some Mediterranean cultures, provide vegetable proteins and polyunsaturated fatty acids.

Tips for conscious purchasing

Choosing quality watermelons requires attention to several indicators. The  percussion of the peel must produce a  dull sound and full sound, an indicator of ripe and sweet pulp. The  patch of earth, or the area that was in contact with the ground, must have a yellowish coloration uniform. The dry peduncle and the presence of light cobwebs on the surface indicate  natural ripening on the plant.

The preference for  local varieties e organic productions supports territorial biodiversity and reducesenvironmental impact of the supply chains (ISPRA, 2024).

The team of  GIFT, Great Italian Food Trade, supports international  buyers in identifying reliable and sustainable suppliers in the fruit and vegetable sector. The experience gained in enhancing the Italian supply chain ensures  traceability, quality and respect of socio-environmental criteria, for the promotion of Italian territorial excellences on global markets.

Conclusions

The Italian watermelon represents a  heritage of biodiversity, tradition and innovation that deserve enhancement and protection. From  terroirs historical ofEmilia-Romagna and the  Apulia to the autochthonous Sardinian varieties, each territory expresses a history of adaptation and selection that has produced  excellences also recognized at the scientific level.

The increasing evidence on  benefits for cardiovascular health, combined with antioxidant properties and support for hydration, make watermelon a  functional food of primary interest. The promotion of  conscious consumption, privileging local and sustainable productions, contributes to individual well-being but also to the conservation of a agricultural heritage that represents the Italian productive identity.

Dario Dongo

Credit cover: Azienda agricola Sarzi Maddidini Fabiano, Marcaria (MN)

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