Summer (Subarctic) versus Winter (Subtropic) Production Affects Spinach (Spinacia oleracea L.) Leaf Bionutrients: Vitamins (C, E, Folate, K₁, provitamin A), Lutein, Phenolics, and Antioxidants

Abstract

Comparison of spinach (Spinacia oleracea L.) cultivars Lazio and Samish grown during the summer solstice in the subarctic versus the winter solstice in the subtropics provided insight into interactions between production environment (light intensity), cultivar, and leaf age/maturity/position affecting bionutrient concentrations of vitamins (C, E, folate, K1, provitamin A), lutein, phenolics, and antioxidants. Growing spinach during the winter solstice in the subtropics resulted in increased leaf dry matter %, oxidized (dehydro) ascorbic acid (AsA), α- and γ-tocopherol, and total phenols but lower reduced (free) AsA, α-carotene, folate, and antioxidant capacity compared to summer solstice-grown spinach in the subarctic. Both cultivars had similar bionutrients, except for higher dehydroAsA, and lower α- and γ-tocopherol in 'Samish' compared to 'Lazio'. For most bionutrients measured, there was a linear, and sometimes quadratic, increase in concentrations from bottom to top canopy leaves. However, total phenolics and antioxidant capacity increased basipetally. The current study has thus demonstrated that dehydroAsA, α-tocopherol, and γ-tocopherol were substantially lower in subarctic compared to subtropical-grown spinach, whereas the opposite relationship was found for antioxidant capacity, α-carotene, and folates (vitamin B9). The observations are consistent with previously reported isolated effects of growth environment on bionutrient status of crops. The current results clearly highlight the effect of production environment (predominantly radiation capture), interacting with genetics and plant phenology to alter the bionutrient status of crops. While reflecting the effects of changing growing conditions, these results also indicate potential alterations in the nutritive value of foods with anticipated shifts in global climatic conditions.

Evaluation and correlation of sensory attributes and chemical compositions of emerging fresh produce: Microgreens

“…Total phenolic content (TPC) was measured using the direct, phenolic-binding Fast Blue BB (FBBB) assay according to the procedure of by Lester et al (2013). Briefly, lyophilized microgreens sample (0.1 g) was extracted with 10 mL of 80% methanol by sonicating for 30 s. The extraction mixture was washed by adding 4 mL of hexane and sonicating for 30 s. After centrifugation at 6650 Â g for 5 min at 4 C, the hexane layer was discarded.…”

Comparison of industrial precooling systems for minimally processed baby spinach

“…Therefore, baby spinach in winter showed higher hydration capacity throughout the whole process. Differences between trials may be related to the effect of variety or to the growing conditions (Lester et al, 2013). For leafy greens, it is critical to maintain hydration (Kader, 1992;Wright, 2004), although water excess can promote the growth of spoilage microorganisms and reduce the shelf life of the product (Herner and Krahn, 1973;Medina et al, 2012).…”

Time of day for harvest and delay before processing affect the quality of minimally processed baby spinach

“…In winter, the effect of HT and DP on the quality characteristics was less marked when compared with spring. Differences between trials may be related to the effect of variety and/or seasonal conditions (Varoquaux et al, 1996;Gruda, 2005;Lester et al, 2013;Singh et al, 2014).…”