Summer is here and it’s time for peaches! In this article I’ll be talking about this fruit, the various cultivars present on the market (at present), and how best to preserve it.
I had already written about peaches and the most famous drink made with this fruit, the Bellini, in 2015 in BarTales (click here, page 64). I decided to keep the two articles separate on the blog so that I could go into more detail on both topics. If however, you’re a Rossini drink lover, you can already find an article on this drink on the blog. If you’re interested in reading it click here.
Let’s start with a bit of history and some general info about this plant and its fruit.
When we talk about peaches we refer to the fruit of the Prunus persica, commonly called peach in jargon. The specific name ‘persica’ suggests that in the past the plant was considered to be originally from Persia (presently Syria) but in fact it is originally from China, as evidenced by some writings dating back to 1,000 BC. It arrived in Europe in the 1st century B.C., thanks to the Romans.
The plant can reach up to 10 meters in height, it has a smooth trunk with a dark gray color bark and its roots can reach 60 cm in depth. It can live up to 30 years, but commercially only plants up to 15 years old are used. Its flowers usually have five variable color petals, from white to dark pink. The maturation period of Italian varieties is from June to September.
Its fruit is a drupe that can be round, elongated or flat, and the ones placed on the market weigh between 180 and 230 grams.
Let’s now have a look at some of the characteristic traits that allow an initial classification of this fruit from a morphological point of view.
– The skin is thin and its color varies from yellow to red. It may have a slight fuzzy coating or it could be smooth; peaches with smooth skin are called nectarines.
– The mesocarp (pulp) encloses a pit that can be either adherent (clingstone peaches) or non-adherent (freestone peaches).
– In addition to the peel type, another parameter commonly used in the classification of the varieties (or cultivars) of peaches is the color of the pulp: yellow or white. This depends on the presence, or lack of, some xanthophils (especially lutein and zeaxanthin), substances belonging to the carotenoids family.
Clearly, the difference between these two is not limited to color alone, but also to the different aromatic profile.
Peaches in Italy
Italy is one of the world’s most important peach producers. Our country has been cultivating peaches since 100 B.C.. In central-southern Italy there are more yellow peach cultivations, while in the north, you’ll find white pulp peaches, which are more suitable for a continental climate.
Trying to indicate the cultivar (the variety cultivated) in Italy is practically impossible because there are hundreds.
The fact that there are so many cultivated peach varieties is not necessarily a problem for bartenders; it’s obvious that it is impossible to know and recognize all these cultivars. What is important, however, is to evaluate the peaches you are using, from time to time, to ensure they are commercially available at that particular moment.
Wanting to use a single and precise cultivar for drinks such as a Bellini (or others) isn’t reasonable because during the ripening period of peaches (summer) the varieties sold, from month to month, may vary. By way of example, I attach the maturation table of a white peach cultivated in Emilia Romagna (property Vivai Fratelli Zanzi).
In the article on the Bellini cocktail I shall examine this aspect in more detail.
Taste and flavor.
The taste and flavor of peaches are determined by aromatic components (several hundred), sugars and acids.
The peach’s aroma is composed of a mixture of various groups of volatile compounds. The aldehydes (i.e. hexanals) are responsible for the green odor or the unripe odor. These diminish as maturation progresses. Other components include lactones, typical and very abundant compounds in peaches (hexa-octa decalactones), terpenes such as linalol and esters such as ethyl and methyl acetate, which generally increase as the fruit ripening progresses. Near the senescence, due to fruit fermentation, we find compounds such as ethyl and methyl alcohol, commonly referred to as off-flavors, because they describe a worsening of aromatic qualities.
The sugars that are most present are sucrose, fructose, glucose and sorbitol. In total, peaches contain a sugar content ranging between 9 and 16%. Among the most present is sucrose. There are also other sugars but in quantities that are of little importance.
Peaches contain a good amount of acids, especially malic and citric acid. Ascorbic and succinic acids are also present but in smaller quantities. In total, the percentage of acids ranges between 0.9% and 1.6%. During the ripening process, the amount of acids can also decrease by 30%.
Maturation and preservation.
Peaches are a climacteric fruit therefore, even after harvesting, its aging process continues, while improving its organoleptic characteristics. If you’re not sure what climacteric means, read my BarTales article on page 46.
Unfortunately it’s a very delicate fruit and it deteriorates rather quickly: preservation at room temperature hardly exceeds 5 days in order for it to remain qualitatively acceptable.
Storage in the refrigerator is, however, extremely damaging: it has been proven that keeping the fruit between 2°C and 7°C can lead to cooling damage, such as loss of aromas, darkening of the pulp, floury, or even woody, texture. This temperature range is also called the ‘killing zone’. Contrary to what common sense would lead us to think, to ensure a long storage time without causing damage, the best temperature is about 0°C as demonstrated by the study “Chilling injury in peach and nectarine. Susan Lurie, Carlos H. Crisosto. Postharvest Biology and Technology 37 (2005) 195–208”. Do not be afraid to place peaches at 0 degrees centigrade! In fact, at this temperature, the fruit doesn’t freeze because of its sugar content.
Of course, if you frequently order peaches in your bar, you don’t have to have to take all these precautions, however if you order in bulk with the intention of preserving them for a long time, it’s a good idea to keep them at the right temperature and away from other climacteric-related fruits (such as apples or maracujas).
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