Effect of air-drying temperature on physico-chemical properties, antioxidant capacity, colour and total phenolic content of red pepper (Capsicum annuum, L. var. Hungarian)

Understanding the influence of processing operations such as drying/dehydration, canning, extrusion, high hydrostatic pressure, pulsed electric field, and ohmic heating on the phytochemicals of fruits, vegetables, and grains is important in retaining the health benefiting properties of these antioxidative compounds in processed food products. Most of the previous investigations in the literature on the antioxidants of fruits, vegetables, and grains have shown that food-processing operations reduced the antioxidants of the processed foods, which is also the usual consumer perception. However, in the last decade some articles in the literature reported that the evaluation of nutritional quality of processed fruits and vegetables not only depend on the quantity of vitamin C but should include analyses of other antioxidant phytochemicals and antioxidant activity. Thermal processing increased the total antioxidant activity of tomato and sweet corn. Most importantly, analysis also depends on the condition, type, and mechanism of antioxidant assays used. This review aims to provide concise information on the influence of various thermal and nonthermal food-processing operations on the stability and kinetics of health beneficial phenolic antioxidants of fruits, vegetables, and grains.

/pdf/effect-of-processing-on-phenolic-antioxidants-of-fruits-1prv71vizl.pdf

Effect of Processing on Phenolic Antioxidants of Fruits, Vegetables, and Grains—A Review

Cooking induces many chemical and physical modifications in foods; among these the phytochemical content can change. Many authors have studied variations in vegetable nutrients after cooking, and great variability in the data has been reported. In this review more than 100 articles from indexed scientific journals were considered in order to assess the effect of cooking on different phytochemical classes. Changes in phytochemicals upon cooking may result from two opposite phenomena: (1) thermal degradation, which reduces their concentration, and (2) a matrix softening effect, which increases the extractability of phytochemicals, resulting in a higher concentration with respect to the raw material. The final effect of cooking on phytochemical concentration depends on the processing parameters, the structure of food matrix, and the chemical nature of the specific compound. Looking at the different cooking procedures it can be concluded that steaming will ensure better preservation/extraction yield of phenols and glucosinolates than do other cooking methods: steamed tissues are not in direct contact with the cooking material (water or oil) so leaching of soluble compounds into water is minimised and, at the same time, thermal degradation is limited. Carotenoids showed a different behaviour; a positive effect on extraction and the solubilisation of carotenes were reported after severe processing. © 2013 Society of Chemical Industry

The effect of cooking on the phytochemical content of vegetables

http://ucce.ucdavis.edu/files/datastore/608-90.pdf

Effects of processing on anthocyanins, carotenoids and vitamin C in summer fruits and vegetables

In this research, total phenols, flavonoids, capsaicinoids, ascorbic acid, and antioxidant activity (ORAC, hydroxyl radical, DPPH, and TEAC assays) of fresh and processed (pickled and chipotle canned) Jalapeno and Serrano peppers were determined All fresh and processed peppers contained capsaicin, dihydrocapsaicin, and nordihydrocapsaicin, even though the latter could be quantified only in fresh peppers Processed peppers contained lower amounts of phytochemicals and had lower antioxidant activity, compared to fresh peppers Good correlations between total phenols and ascorbic acid with antioxidant activity were observed Elimination of chlorophylls by silicic acid chromatography reduced the DPPH scavenging activity of the extracts, compared to crude extracts, confirming the antioxidant activity of chlorophylls present in Jalapeno and Serrano peppers

/pdf/antioxidant-activity-of-fresh-and-processed-jalapeno-and-stx67vh5qf.pdf

Antioxidant Activity of Fresh and Processed Jalapeño and Serrano Peppers

Effect of cooking on the antioxidant properties of coloured peppers

Traditional Chinese medicinal herbs have been used for thousands of years to treat numerous ailments. In recent years, these herbs have been the focus of attention due to their medicinal and pharmacological benefits. In the present study, 25 types of herbs commonly used in Chinese medicinal culinary diets were quantitatively investigated for their various antioxidant activities. Using the 1,1-diphenyl-2- picrylhydrazyl high pressure liquid chromatography and 2´-deoxyguanosine oxidation methods, the highest antioxidant activity was found in chrysanthemum (Ju Hua), followed by hawthorn (Shan Zha), licorice root (Gan Cao), hibiscus (Luo Shen Hua), cassia seed (Jue Ming Zi) and Chinese wolfberry (Gou Gi), while poria (Fu Ling) and adlay (Yi Yi Ren) contained the lowest antioxidant activity. The same trend was also observed for total phenolic content using the Folin-Ciocalteu method. Ascorbic acid and tocopherol were only detected in trace amounts, suggesting that phenolic compounds may be the main contributors to herbal antioxidant activities.

http://dspace.lib.niigata-u.ac.jp/dspace/bitstream/10191/17996/1/14_205.pdf

Ya-Chi Lee

Papers

Effect of cooking on the antioxidant properties of coloured peppers

Antioxidant Activity of Traditional Chinese Medicinal Herbs