Agriculture Reference
In-Depth Information
5
Novel Processing Technologies for Fruits
Jasim Ahmed and Ferhan Ozadali
INTRODUCTION
Fruits are perishable in nature, requiring immediate pro-
cessing to enhance shelf life. Conventional processing
(thermal processing, freezing, drying) is mostly used to
preserve fruit products. The major quality attributes of
thermally processed fruit are color, aroma, taste, and tex-
ture, while hidden quality attributes like nutritional value
and safety (chemical and microbiological) remain the most
challenging concern in processed fruit. Conventional pro-
cessing fails to produce fruit products with desirable quality
and sensory attributes that match what today's consumers
are constantly looking for. In the last few years, there has
been growing research and commercial interest in nonther-
mal techniques to preserve fruit-based products. In addi-
tion, to find a technological edge in the marketplace, fruit
processors are exploring new processing and preservation
technologies.
Numerous novel food processing technologies are cur-
rently being explored for translating pilot plants to com-
mercial scale, some of which have been recognized and
approved by regulatory agencies for use in food process-
ing. The major hurdles before commercialization of any
novel technology are process validation and ensuring prod-
uct safety. Among novel technologies, high-pressure pro-
cessing (HPP) has been approved for the pasteurization of
specific products; its approval in the United States for use as
a processing alternative in combination with thermal pro-
cessing for sterilization has also been announced (NCFST,
2009).
Novel technologies can be classified into two categories:
electrotechnologies (pulse electric field, radio frequency
[RF] heating, microwave heating, infrared heating, ohmic
heating, etc.), which make use of novel methods of heat-
ing, and nonthermal technologies (pulse-light, HPP, oscil-
lating magnetic field, irradiation, ozonation, plasma, os-
motic treatment, etc.) (Ahmed et al., 2010). Most of the
electrotechnologies focus on novel approaches to gener-
ate heat and rely on conventional thermal mechanisms for
achieving preservation and processing. Nonthermal pro-
cessing technologies, conversely, inactivate enzymes and
micro-organisms and modify the functional properties of
food by alternate means without substantially increasing
the product temperature.
Commercialization of the emerging technologies re-
quires high capital expenditures that need justifiable ben-
efits over the existing technologies and investments. Since
these technologies are developed at the laboratory or pilot
plant scale, full-scale operational cost and the impact on
the product are unknown and are obviously a significant
financial, safety, and quality risk for the processor (Ahmed
et al., 2010).
This chapter focuses on applications of some novel food
processing technologies (such as HPP, pulsed electric field
[PEF], ohmic heating, microwave and RF heating) to fruit
products and their effect on quality attributes and shelf life.
HIGH-PRESSURE PROCESSING (HPP)
Pressure is an important thermodynamic parameter which
can intensely influence molecular systems. However, the
effects of high pressure (HP) on living systems and
biomolecules have not received the same attention as
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