Effect of steam sterilisation on lipophilic nutrient stability in a chloroplast-rich fraction (CRF) recovered from postharvest, pea vine field residue (haulm).

Postharvest, pea vine field residue (haulm) was steam-sterilised and then juiced; a chloroplast-rich fraction (CRF) was recovered from the juice by centrifugation. The stability of selected nutrients (ß-carotene, lutein, and α-tocopherol) in the freeze-dried CRF material was measured over 84 days; the impact of temperature (-20 °C, 4 °C, 25 °C and 40 °C), light and air on nutrient stability was established. All three nutrients were stable at -20 °C and 4 °C in the presence or absence of air; this stability was lost at higher temperatures in the presence of air. The extent and rate of nutrient breakdown significantly increased when the CRF samples were exposed to light. ß-Carotene appeared to be more susceptible to degradation than lutein and α-tocopherol at 40 °C in the presence of air, but when CRF was exposed to light all three nutrients measured were significantly broken down during storage at 25 °C or 40 °C, whether exposed to air or not.

Chloroplast-rich material from the physical fractionation of pea vine (Pisum sativum) postharvest field residue (Haulm).

An innovative procedure for plant chloroplasts isolation has been proposed, which consists of juice extraction by physical fractionation from plant material and recovery of its chloroplast-rich fraction (CRF) by centrifugation. This simple method has been applied to pea vine haulm subjected to different post-harvest treatments: blanching, storage at different relative humidity values and fermentation. Additionally, freeze storage of the extracted juice was carried out. The macronutrient (total lipids, proteins, ash and carbohydrates) and micronutrient (fatty acids, chlorophylls, ß-carotene, α-tocopherol and ascorbic acid) content and composition of the CRF have been determined. The CRF isolated from fresh pea vine haulm is a potential source of essential micronutrients (α-linolenic acid, ß-carotene, α-tocopherol) and carbohydrates, whereas the post-harvest treatments trialled have a detrimental effect on the nutritional content. Industrial applications for the recovered nutritionally rich fraction, such as food supplement ingredient or animal feeding, are likely envisaged, while optimising the use of green haulm.

Component analysis of nutritionally rich chloroplasts: recovery from conventional and unconventional green plant species.

A study of the literature indicates that chloroplasts synthesise a range of molecules, many of which have nutritional value for humans, but the nutritional credentials of chloroplasts recovered from plant cells are not established. Chloroplast-rich-fractions (CRFs) were prepared from green plant species and the macro- and micro-nutrient composition compared with the whole leaf materials (WLMs). The results indicated that, on a dry weight basis, CRF material from a range of green biomass was enriched in lipids and proteins, and in a range of micronutrients compared with the WLM. Vitamins E, pro-vitamin A, and lutein were all greater in CRF preparations. Of the minerals, iron was most notably concentrated in CRF. Spinach CRFs possessed the highest α-tocopherol [62 mg 100 g-1, dry weight (DW)], ß-carotene (336 mg 100 g-1 DW) and lutein (341 mg 100 g-1 DW) contents, whilst grass CRFs had the highest concentration of alpha-linolenic acid (ALA) (69.5 mg g-1). The higher concentrations of α-tocopherol, ß-carotene, lutein, ALA and trace minerals (Fe and Mn) in CRFs suggested their potential use as concentrated ingredients in food formulations deficient in these nutrients.