Antioxidant Protection Factor Research Articles

SOLID-STATE PRODUCTION OF PHENOLIC ANTIOXIDANTS FROM CRANBERRY POMACE BY RHIZOPUS OLIGOSPORUS

ABSTRACT Cranberry pomace is a byproduct of the cranberry processing industry that can be targeted for production of value-added phenolic ingredients. Bio-processing of pomace by solid state fermentation (SSF) using food grade fungi provides unique strategies to improve nutraceutical properties and to produce functional phenolic ingredients. Several functional phenolic phytochemicals exist as glycosides or as other conjugated forms with reduced biological activity. We hypothesize that during SSF the fungal glycosidases mobilize some phenolic antioxidants in cranberry pomace and their activity by hydrolysis via β-glucosidase and releasing the aglycone. To develop this strategy we used food grade fungus Rhizopus oligosporus. Our goal was to target the release of simple phenolic aglycones and mobilized diphenyls. SSF of cranberry pomace was done for 16 days with nitrogen sources, ammonium nitrate (NH4NO3) and fish protein hydrolysate (FPH). The two nitrogen treatments increased water extractable phenolics by 15–26% by day 10 in the pomace. Antioxidant protection factor was highest on day 10 for both nitrogen treatments and was 20–25% higher than control for water extracts and 16.5–19.5% for ethanol extracts. The DPPH radical inhibition (DRI) capacity increased by 5% only for the NH4NO3 treatment and gradually decreased for FPH treatment in water extracts. There was no significant change in DRI of the ethanol extracts. The β-glucosidase activity increased by 60-fold for NH4NO3 treatment and by over 100-fold for FPH treatment and correlated well with the increase in the extractable phenolics and antioxidant activity. Changes in diphenyl profiles during the solid-state process analyzed using HPLC indicated that ellagic acid increased by 4–5 fold in water extracts for both the nitrogen treatments. This increase was between 15–27% in the ethanol extracts. We conclude that SSF of cranberry pomace increased the antioxidant activity concurrent with increased β-glucosidase activity. The HPLC profile showed ellagic acid, a compound with anti-carcinogenic properties was enriched. The antioxidant function has implications for prevention of major oxidation-linked diseases such as cancer and CVD. This value-added SSF strategy is an innovative approach to enhance nutraceutically-relevant functional phytochemicals for food and feed applications.

THE STIMULATION OF PHENOLICS AND ANTIOXIDANT ACTIVITY IN PEA (PISUM SATIVUM) ELICITED BY GENETICALLY TRANSFORMED ANISE ROOT EXTRACT

A series of dark germination experiments demonstrate the potential of an Agrobacterium rhizogenes-transformed, high cytokinin root extract of anise (Pimpinella anisum), to stimulate phytophenolic and enhance antioxidant activity in pea (Pisum sativum) seedlings. Average shoot weight increased 40–60% after imbibing seeds for 24 h in a 1.5 to 2.0% extract of the anise root clone AR-10. Phenolic concentration was positively correlated with shoot weight, suggesting that the total phenolic content was related to seedling vigor. Antioxidant protection factor in pea shoots was also stimulated by AR-10 extracts. Free proline concentrations were 2–3 times higher in shoots collected from AR-10 treated peas versus controls. However, proline content also increased as shoot weight declined after being subjected to an overdose of AR-10 extract in 25% ethanol. G6PDH specific activity, the first committed step of the pentose phosphate pathway, was negatively associated with shoot growth and proline concentrations.

Phenolic compounds and antioxidant properties in the snow alga Chlamydomonas nivalis after exposure to UV light

The snow alga Chlamydomonas nivalis was collected from the Sierra Nevada, California, USA, and examined for its ability to produce phenolic compounds, free proline, and provide antioxidant protection factor in response to UV-A and UV-C light. Exposure of C. nivalis cells to UV-A light (365nm) for 5 days resulted in a 5–12% increase in total phenolics, where as exposure to UV-C light (254 nm) resulted in a 12–24% increase in phenolics after 7 days of exposure. Free proline was not affected by UV-A, but increased markedly after UV-C exposure. A three-fold increase in free proline occurred within two days after exposure to UV-C, but then dropped as cells became bleached. Antioxidant protection factor (PF) increased after treatment of cells with UV-A and remained constant throughout UV-C exposure. Spectral analysis of algal extracts revealed a decrease in absorption in the 215–225 nm region, short-term (2day) stimulation of pigment at 280 nm, and an increase in carotenoids (473 nm), after exposure to UV-A. Snow alga exposed to UV-C light had a different spectrum from that of UV-A exposed cells, i.e. an enhancement of three major peaks at 220, 260, and 280 nm, and loss of absorption in the carotenoid region.We report that UV light exposure, especially in the UV-C range, can stimulate phenolic-antioxidant production in aplanospores of C. nivalis effecting biochemical pathways related to proline metabolism.