FREEZING METHOD FOR RASPBERRIES AND BLUEBERRIES USING LIQUID NITROGEN

Autor/autori: Valeriu DAMIAN , Cristian IOSIFESCU , Gelu COMAN

Rezumat: Metoda prezentata foloseste pentru congelare azot lichid, care are avantajul costului redus, fiind obtinut ca produs secundar in urma procesului de separare a aerului. Lucrarea prezinta aspecte legate de congelarea criogenica cu azot lichid a fructelor de padure (zmeura si afine): durata procesului, influenta a diferiti parametri, avantajele si dezavantajele metodei. Congelarea rapida consta in folosirea intr-un congelator criogenic atat a caldurii latente de vaporizare a azotului lichid, cat si a caldurii specifice a vaporilor de azot formati, a caror temperatura creste pana la temperatura finala a produsului congelat.

Cuvinte cheie: congelare criogenica, fructe de padure, conservarea alimentelor.


Abstract: Considering the demands for reduction of fuel consumption involved in generation of electrical energy needed for classical refrigeration systems, this method uses for freezing liquid nitrogen obtained as secondary product at oxygen production. The resulted nitrogen gas is discharged in the environment, and, being chemically inert, it does not contribute to generation of harmful chemical components. This paper presents some aspects concerning raspberries and blueberries freezing using liquid nitrogen: duration of the process, influence of various parameters, advantages and disadvantages of this modern method. Quick freezing of food products in a cryogenic freezer consist in the use latent heat of evaporation of the liquid nitrogen, as well as of the sensible heat of the vapors, whose temperature increase up to final temperature of the frozen product.

Keywords: berries, freezing, food preservation, nitrogen

 

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