Brand new test is included with silicone polymer fat to waterproof the material. Apparent frequency try mentioned that have an excellent steropycnometer ( Loch-Bonazzi although Trans Singles Dating-Seite some 1992 ).
Present, very appropriate methods for computing obvious regularity was proposed, in addition to laser beam researching ( Uyar and you can Erdogdu 2009 ; Kelkar while some 2011 ), automated tomography ( Mendoza although some 2007 ; Kelkar while some 2011 ), and you can magnetic resonance imaging ( Kelkar while others 2011 ). Such procedure incorporate optic equipment and you will authoritative application in order to processes and carry out three dimensional photos out of objects, figuring frequency that have limited variations otherwise limited ability. not, the fresh downsides of them processes exceed the pros, given that a specific background becomes necessary, in addition to official equipment that’s way more costly than antique process.
Collection from Studies
Lots of functions has actually handled the fresh choices off true and you may noticeable occurrence, both in the brand new drying techniques plus in the newest rehydration regarding food items (Table 1 and you may 2). These studies view multiple food confronted by some drying standards and you will in different geometric shapes. The fresh new details that have been learned are as follows: tension (P), cousin humidity (RH), drying out sky speed (?), and drying temperatures (T), among others. Pretreatments such as blanching, coatings, and you will osmotic dehydration, among others, was indeed said ( Boukouvalas although some 2006 ).
Conventional convective drying, microwave drying, osmotic drying, spray-drying, vacuum-drying out, and you will lyophilization will be the most often used methods; they’ve been examined lower than both lingering and you may adjustable functioning standards ( Pezzutti and C ; Doymaz and you may Pala 2002 ). Content dried by convective means try characterized by its reduced porosity and you will high visible occurrence ( Zogzas and others 1994 ). Comparable attributes had been claimed for product dehydrated on microwave approach, due to the fact that a mix of these types of dos procedures tends to be put ( Krokida although some 2000 ). Osmotic dehydration leads to a boost in obvious density for the majority product, and you will a drop for others. This event has been caused by the increase during the solids through the this new osmotic procedure ( Krokida and you may Maroulis 1997 ). Lyophilization returns factors having lower occurrence, due to their porosity; this process supplies the very best quality end result, as there are zero deformations throughout the issue, color and you can fragrance is actually kept. Nonetheless, it does have the downside to be high priced and you can demanding long drying out periods ( Krokida and you can ).
Several architectural variables out of food items was analyzed in lyophilization techniques. Sablani and others (2007) found that noticeable thickness, true occurrence, and porosity try a function of water blogs (X) and you can dish heat; although not, there’s too little clarity during these inclinations ( Karathanos while some 1996 ; Sablani while some 2007 ; Oikonomopoulou although some 2011 ).
The consequences out-of drying conditions into the density
Particular article writers have discovered that effect of relative humidity for the real and you will apparent density are minimal ( Zogzas and others 1994 ). As the effects of drying out sky acceleration towards the thickness haven’t already been studied, you’ll be able to compile study out-of certain bibliographic present referring to at least one thing; instance investigation suggest that real and you will apparent density was lower at lower drying heavens velocities (Dining table 1). Yet not, after that research on the subject is required. Pair studies have stated towards the negative effects of brand new geometry away from the information presented on the occurrence, although it is known in order to determine visible occurrence viewpoints. Such as for example, the newest density out of entire garlic cloves has a concave-down contour regarding X; having said that, garlic cloves sliced in two display a beneficial linear, ascendant inclination with respect to the reduced total of X ( Lozano although some 1983 ).
