Effects of high hydrostatic pressure on chlorophylls and chlorophyll–protein complexes in spinach

Natural chlorophyll: a review of analysis methods, health benefits, and stabilization strategies

Chlorophyll (Chl) is a natural pigment, widely distributed ranging from photosynthetic prokaryotes to higher plants, with an annual yield of up to 1.2 billion tons worldwide. Five types of Chls are observed in nature, that can be distinguished and identified using spectroscopy and mass spectrometry. Chl is also used in the food industry owing to its bioactivities, including obesity prevention, inflammation reduction, viral infection inhibition, anticancer effects, anti-oxidation, and immunostimulatory properties. It has great potential of being applied as a colorant and dietary supplement in the food industry. However, Chl is unstable under various enzymatic, acidic, heat, and light conditions, which limit its application. Although some strategies, such as aggregation with other food components, microencapsulation, and metal cation replacement, have been proposed to overcome these limitations, they are still not enough to facilitate its widespread application. Therefore, stabilization strategies and bioactivities of Chl need to be expected to expand its application in various fields, thereby aiding in the sustainable development of mankind.

Effects of ultra-high pressure, thermal pasteurization, and ultra-high temperature sterilization on color and nutritional components of freshly-squeezed lettuce juice

The aim of this study was to evaluate the effects of ultra-high pressure (UHP, 600 MPa/2 min), thermal pasteurization (TP, 95 °C/1 min) and ultra-high temperature (UHT, 115 °C/5 s) sterilization on the color, sensory evaluation, microorganisms, physicochemical characteristics and nutritional components of freshly-squeezed lettuce juice (FLJ). Results showed that three sterilization methods demonstrated desirable inactivation effects on total aerobic bacteria, yeast and mold, and there were no significant changes in the main nutritional components, including ash, protein, carbohydrate and total dietary fiber. However, UHT and TP significantly affected the color of FLJ from bright green to light brown and made chlorophyll, β-carotene and vitamins (VE, VC, VK1, VB6, VB12, and folic acid) contents markedly decreased. By contrast, UHP maintained the original color, fresh-like sensory qualities, vitamins, and carotene of FLJ to the greatest extent. Our results provide a promising application of UHP in the large-scale processing of FLJ.

Functional relationship of vegetable colors and bioactive compounds: Implications in human health

Vegetables are essential protective diet ingredients that supply ample amounts of minerals, vitamins, carbohydrates, proteins, dietary fiber, and various nutraceutical compounds for protection against various disease conditions. Color is the most important quality parameter for the farmers to access the harvest maturity while for the consumer's reliable indices to define acceptability or rejection. The colored vegetables contain functional compounds like chlorophylls, carotenoids, betalains, anthocyanins, etc. well recognized for their antioxidant, antimicrobial, hypolipidemic, neuroprotective, antiaging, diuretic, and antidiabetic properties. Recently, there has been a shift in food consumption patterns from processed to semi-processed or fresh fruits and vegetables to ensure a healthy disease-free life. This shifted the focus of agriculture scientists and food processors from food security to nutrition security. This has resulted in recent improvements to existing crops like blue tomato, orange cauliflower, colored and/or black carrots, with improved color, and thus enriched bioactive compounds. Exhaustive laboratory trials though are required to document and establish their minimum effective concentrations, bioavailability, and specific health benefits. Efforts should also be directed to breed color-rich cultivars or to improve the existing varieties through conventional and molecular breeding approaches. The present review has been devoted to a better understanding of vegetable colors with specific health benefits and to provide in-hand information about the effect of specific pigment on body organs, the effect of processing on their bioavailability, and recent improvements in colors to ensure a healthy lifestyle.