Forced-air, vacuum, and hydro precooling of cauliflower (Brassica oleracea L. var. botrytis cv. Freemont): part I. determination of precooling parameters

Abstract

The aim of the present study was to precool cauliflower using forced-air, vacuum and high and low flow hydro cooling methods. The weight of the precooled cauliflower heads (5000±5 g) was measured before they were placed in standard plastic crates. Cauliflower heads, whose initial temperature was 23.5 ± 0.5 °C, were cooled until the temperature reached at 1 °C. During the precooling process, time-dependent temperature and energy consumption were measured, and during vacuum precooling, the decreasing pressure values were recorded, and a curve of time-dependent pressure decrease (vacuum) was built. The most suitable cooling method to precool cauliflower in terms of cooling time and energy consumption was vacuum, followed by the high and low flow hydro and forced-air precooling methods, respectively. The highest weight loss was observed in the vacuum precooling method, followed by the forced-air method. However, there was an increase in the weight of the cauliflower heads in the high and low flow hydro precooling method. The best colour and hardness values were found in the vacuum precooling method. Among all methods tested, the most suitable method to precool cauliflower in terms of cooling and quality parameters was the vacuum precooling method.

<b>Combination of optimization techniques to find of processing optimal condition of postharvest broccoli by vacuum cooling process

“…The water-spraying volume can be controlled by this system. In this study, the pressure in vacuum chamber (200, 400, and 600 Pa), water-spraying volumes (3, 4, and 6%), and processing time (20, 30, and 40 min) were applied for the purpose of investigating their synthetic effects on the weight loss of broccoli during the vacuum cooling processing (Alibas & Koksal, 2014). The weight was calculed by Equation 1.…”

“…However, it was still unclear how many spraying water is suitable to apply in vacuum cooling process. Besides, preliminary studies indicated that many other factors such as vacuum degree, weight of treated broccoli samples, and treatment time can also influence the weight loss of products significantly (Alibas & Koksal, 2014).…”

“…The vacuum cooling technique was applied to other types of vegetables like cauliflower, peppers, sweetcorn, onions, carrots (Alibas & Koksal, 2014). Fruits such as strawberry, gooseberry and melon, and vegetables such as cabbage, turnips, eggplant and cucumber, have also been objects of study for the application of vacuum cooling (McDonald et al, 2000).…”

Enginarın basınçlı havayla, suyla ve vakumla ön soğutulmasının depolama koşullarındaki kalite parametreleri üzerindeki etkisinin belirlenmesi

“…En fazla gücün harcandığı vakumla ön soğutma yöntemindeki güç gereksiniminin, havayla ön soğutma yöntemindeki güç gereksinimine göre 1.75 kat fazla olduğu saptanmıştır. Enerji ve güç tüketimi ile ilgili benzer sonuçlar literatür çalışmaları ile paralellik göstermektedir (Alibaş & Okursoy 2012;Alibas & Koksal 2014). Ön soğutma işlemlerinin sonunda suyla ön soğutulmuş ürünlerde % 2.83 değerinde bir ağırlık artışı, havayla ve vakumla ön soğutulmuş enginarlarda ise sırasıyla % 1.03 ve % 1.88 değerinde bir ağırlık kaybı saptanmıştır.…”

“…Soğutucu akışkan olarak kullanılan havanın soğutulacak olan materyalin bulunduğu ortama gönderilmesi ile havayla ön soğutma işlemi gerçekleştirilmektedir. Hasat sıcaklığındaki ürün, soğuk havanın etkisi ile dış yüzeyden başlayarak iç yüzeye doğru konveksiyon yoluyla soğutulmaktadır (Alibas & Koksal 2014). Suyla ön soğutma yönteminde soğutulmuş su, soğutucu akışkan olarak sisteme verilir ve ürünlerin soğuması tıpkı havayla ön soğutma yöntemindeki gibi konveksiyon yoluyla sağlanmaktadır (Alibaş & İzli 2013).…”