Panna Cotta, although now acknowledged as an iconic Italian dessert, only appeared on the Italian culinary scene after 1960 from the Langhe wine region in Piedmont, Northern Italy, where cream is abundant. The mark of a perfect panna cotta is stability, writes foodie Roberta Schira, so that the quantity of thickener (often gelatine) can be reduced as much as possible without compromising structure, consistency and creaminess. It should not wobble “like a girl perched on high-heeled shoes”, but should only just hold together. It should be so slightly set that it should barely make it intact from the kitchen to the table. Roberta continues that ultimately one should strive to never exceed 8 grams of gelatin for every 500 ml of liquid, which is highly challenging when one makes a papaya Panna Cotta, as in the recipe below.
The culprit here is a cysteine protease enzyme (papain) in the papaya, which breaks down the peptide bonds between amino acids and can only be rendered inactive by the application of heat. Papain is the English translation of ‘papaïne’, the name given by Wurtz and Bouchut to a proteolytically active constituent in the latex of the tropical papaya fruit (Carica papaya) (Storer & Ménard, 2013:1858). The enzyme is also often used in toothpaste as a teeth whitener. Cooking papaya, however, is not a good solution, since doing so will dull the freshness of the fruit. Food Science guru Harold McGee writes in his eminent food reference guide, McGee on Food & Cooking (2004:607), that a number of other fruits, like pineapple and kiwi, also contain protein-digesting enzymes that break gelatine chains into short pieces and prevent them from setting into a gel. Information on how long it takes for the enzyme to digest the protein is scarce, so it would be best to make and chill the panna cotta until fully set, and then serve it immediately before the enzymatic action turns it into a soupy mess. This is a real balancing act for the cook who wishes to achieve a gentle wobble, and not a puddly soup.
Ingredients for 4 portions:
115 g heavy papaya purée (see note below)
Scraped out seeds of 1 vanilla pod
150 g fresh cream
30 g honey
3 teaspoons (15 ml) granulated gelatine (vegans may also experiment with agar-agar as a setting agent)
150 g thick double cream plain Greek yoghurt
Sprinkle the granulated gelatine on half of the fresh cream. Leave it to fully bloom.
Melt it down in the microwave oven or over boiling water.
Stir and add the remaining cream into the mixture.
Ensure that the drained papaya purée is smooth, or thoroughly whisk it together with the yoghurt.
Stir in the vanilla, honey and the melted gelatine cream mixture.
Pour into four lightly greased moulds or in pretty presentation cups if you do not plan to unmould the panna cottas.
Serve with small balls of fresh papaya, papaya coulis and decorate with small edible flowers.
The overall moisture content of papaya purée may be too high to incorporate directly into a panna cotta mixture. To make the heavy papaya purée, peel and de-seed a thoroughly ripe, aromatic papaya (unripe papaya contains higher levels of papain than ripe papayas). Blend the papaya flesh in a food processor, liquidizer or with a stick-blender in a tall jar, to get a smooth purée (strain through a fine sieve if you are uncertain that your purée is lump-free). Line a sieve with a clean, rinsed layer of high-quality muslin cloth. Pour the purée onto the muslin, cover with plastic wrap and leave overnight in the fridge for the liquid to drain out and the papaya purée to become thick and jelly-like.