March 2019
Univeristà degli Studi di Teramo
Author Name: 
Valeria Di Giandomenico
Tutor name: 
Lilia Neri
Co-tutor name: 
Veronica Santarelli

In recent years, consumers have shown a growing interest in healthy foods with high sensory
and nutritional quality. On the industrial scale, this led to higher attention towards products’
quality indices strictly related to those perceived and requested by consumers.
Vacuum impregnation (VI) is a unit operation that permits a faster and more homogenous
impregnation of fruit and vegetable porous tissues with selected compounds compared to the
classical diffusion processes. By VI various substances can be introduced inside plant food
matrix and depending on the type of these components, the final product can be characterized
by modified/improved sensorial quality, an extended shelf-life and/or fortified with bioactive
compounds the aim to increase the daily intake and meet nutritional recommendation or
health benefits. To this regard, plant extract such as Green tea (GT) extract, which have a high
content in bioactive compounds have been used recently for food fortification (Tappi et al.,
The frozen food industry plays an important and growing role in the food sector, especially in
the vegetable one. The use of low temperatures below the freezing point allows to preserve
safety and nutritional during shelf life. However, frozen products, upon thawing, may show
undesirable losses of exudates, color changes and softening due to both freezing and thawing
as well as due to freezing pre-treatments.
Blanching is a thermal pre-treatment for the enzymatic stabilization of plant products
intended for frozen storage. This pre-treatment, however, can lead to undesired loss of
bioactive compounds and damages to plant structures. Hence, the need and interest of the
food industry to identify new strategies and ingredients aimed at limiting the quality loss
determined by this treatment.
The aim of this work was to improve the quality and stability of frozen carrots by adding
functional ingredients from a technological and health point of view. Pre-treatment of
blanching and vacuum impregnation has been used to promote the penetration of trehalose
and/or green tea extract into the plant tissue. Trehalose is a non-reducing disaccharide, able to
stabilize and protect cellular structures during thermal treatments conducted at both high and
low temperatures (Neri et al, 2011; Neri et al., 2014), while green tea represents a rich source
of phenolic compounds with show antioxidant activity both in in-vitro and in-vivo.
The qualitative characteristics of the fresh (not pre-treated) and differently pre-treated samples
were evaluated immediately after the impregnation treatment and after freezing and storage at
low temperatures (-18 ° C) for 7 and 60 days.

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