Agriculture Reference
In-Depth Information
16.6 Apple postharvest preservation is linked to phenolic
phytochemicals and superoxide dismutase activity
The biochemical factors affecting postharvest preservation in apples indicated that well-
preserved varieties of apples had increased SOD activity initially, and the activity declined
during later storage as apples deteriorated (Adyanthaya et al., 2008a). The SOD link to
better preservation correlated with higher phenolic content and free radical-scavenging-
linked antioxidant activity. Well-preserved varieties were able to maintain a more stable
pentose phosphate pathway (PPP) (measured by the activity of glucose-6-phosphate dehy-
drogenase, G6PDH) throughout the storage period. Proline content increased in all varieties
with an increase in proline dehydrogenase (PDH) activity in the initial period indicating
proline catabolism, supporting potential ATP synthesis. During later storage, SDH activity
increased, while PDH activity declined indicating a shift to tricarboxylic acid cycle and
likely NADH generation for ATP synthesis. This shift coupled with the declining SOD ac-
tivity coincides with rapid deterioration. The GPX activity generally declined in late stages
indicating postharvest deterioration.
16.7 Health benefits of apple phenolics from postharvest stages
for potential diabetes management using in vitro models
Increasing number of studies has shown that regular intake of fruits and vegetables have
clear links to reduced risk of chronic diseases like diabetes and cardiovascular disease.
The beneficial effects in many cases have been attributed to the phenolic and antioxidant
content of the fruits and vegetables. Apples are a major source of fiber and contain good
dietary phenolics with antioxidant function. Previous epidemiological studies have indi-
cated that intake of apples reduces the risk of developing type 2 diabetes. Our studies
indicate that this reduced risk is potentially due to modulation of postprandial glucose in-
crease by phenolics present in apples via inhibition of
-glucosidase (Adyanthaya et al.,
2008b). Phenolic content was evaluated during 3 months of postharvest storage of four
varieties of apples, and results indicated positive linkage to enhanced postharvest preser-
vation and
α
-glucosidase inhibition. These in vitro results along with existing epidemio-
logical studies provide strong biochemical rationale for further animal or human clinical
studies.
α
16.8 Antioxidant and bioactive films to enhance food quality and
phytochemicals production during postharvest stages
Consumers have many food choices, and their demand for safer and higher quality “natu-
ral” foods has increased. The entire food production process has a part in providing a more
delicious, safe, and healthy food than in the past. Packaging plays an important role in
maintaining quality and improving storage properties such as color, flavor, odor, microbial
growth, and texture. In general, most foods are packaged to preserve quality. Films are im-
portant for safety since they come in direct contact with foods and the concept of packaging
as only protection is gone. Now, packaging films play an active role in food preservation
because it is possible to add physical, chemical, biochemical, and microbial modulators to
films. Active packaging has been defined as “a type of packaging that changes packaging
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