Comparison of the Total Phenolic and Ascorbic Acid Content of Freeze-Dried and Air-Dried Marionberry, Strawberry, and Corn Grown Using Conventional, Organic, and Sustainable Agricultural Practices

Abstract

Secondary phenolic metabolites play an important role in plant defense mechanisms, and increasing evidence indicates that many are important in human health. To date, few studies have investigated the impact of various agricultural practices on levels of secondary plant metabolites. To address this issue, the total phenolic (TP) content of marionberries, strawberries, and corn grown by sustainable, organic, or conventional cultural practices were measured. Additionally, the effects of three common postharvest processing treatments (freezing, freeze-drying, and air-drying) on the TP content of these agricultural products were also investigated. Statistically higher levels of TPs were consistently found in organically and sustainably grown foods as compared to those produced by conventional agricultural practices. In all samples, freeze-drying preserved higher levels of TPs in comparison with air-drying.

Antioxidant activity as indicator of UV radiation and other abiotic stress factors on Agaricus bisporus (Lange/Imbach) and Sedum hybridum (L.)

“…Alteration in phenolic compound levels was also significant, which is in agreement with the results obtained from test performed on berries (Asami et al, 2003;Murugesan et al, 2012).…”

“…Sambucus sp., Fragaria sp. (Asami et al, 2003;Murugesan et al, 2012). The joint feature of these induction factors is that they both mean stress to the plants.…”

Determination of vitamin C and total phenolic in fresh and freeze dried blueberries and the antioxidant capacity of their extracts

“…Sustainably grown and organic freeze dried blueberries contained higher levels (49%) as compared to the organic fresh and conventionally grown blueberry (43% and 28%). Furthermore the results showed that organically grown fruits and vegetables contain high antioxidant activity than cultivators however this has not been studied conclusively [34].…”

Antioxidant and antimicrobial activities and starch digestion rate of the organically- and non-organically grown traditional rice varieties in Sri Lanka

“…The highest mean TPC was observed for organicallyproduced Madathawalu (MO) while the lowest for non-organically produced Handiran (HN) rice sample. Asami et al (2003) reported that organically produced rice samples show superior TPC results than the non-organically produced samples. Asami et al (2003) also reported 52% more ascorbic acid and significantly higher polyphenol contents in organically grown corn than conventionally grown corn.…”

“…Asami et al (2003) reported that organically produced rice samples show superior TPC results than the non-organically produced samples. Asami et al (2003) also reported 52% more ascorbic acid and significantly higher polyphenol contents in organically grown corn than conventionally grown corn. Among the organically-produced rice varieties, the two red pericarp rice varieties used in this study (Madathawalu -MO, and Handiran -HO) showed…”