Understanding differences in protein fractionation from conventional crops, and herbaceous and aquatic biomass - Consequences for industrial use

Identification of Bioactive Phytochemicals in Leaf Protein Concentrate of Jerusalem Artichoke (Helianthus tuberosus L.)

Jerusalem artichoke (JA) is widely known to have inulin-rich tubers. However, its fresh aerial biomass produces significant levels of leaf protein and economic bioactive phytochemicals. We have characterized leaf protein concentrate (JAPC) isolated from green biomass of three Jerusalem artichoke clones, Alba, Fuseau, and Kalevala, and its nutritional value for the human diet or animal feeding. The JAPC yield varied from 28.6 to 31.2 g DM kg-1 green biomass with an average total protein content of 33.3% on a dry mass basis. The qualitative analysis of the phytochemical composition of JAPC was performed by ultra-high performance liquid chromatography-electrospray ionization-Orbitrap/mass spectrometry analysis (UHPLC-ESI-ORBITRAP-MS/MS). Fifty-three phytochemicals were successfully identified in JAPC. In addition to the phenolic acids (especially mono- and di-hydroxycinnamic acid esters of quinic acids) several medically important hydroxylated methoxyflavones, i.e., dimethoxy-tetrahydroxyflavone, dihydroxy-methoxyflavone, hymenoxin, and nevadensin, were detected in the JAPC for the first time. Liquiritigenin, an estrogenic-like flavanone, was measured in the JAPC as well as butein and kukulkanin B, as chalcones. The results also showed high contents of the essential amino acids and polyunsaturated fatty acids (PUFAs; 66-68%) in JAPC. Linolenic acid represented 39-43% of the total lipid content; moreover, the ratio between ω-6 and ω-3 fatty acids in the JAPC was ~0.6:1. Comparing the JA clones, no major differences in phytochemicals, fatty acid, or amino acid compositions were observed. This paper confirms the economic and nutritional value of JAPC as it is not only an alternative plant protein source but also as a good source of biological valuable phytochemicals.

Application of lactic acid bacteria in green biorefineries

Lactic acid bacteria (LAB) have extensive industrial applications as producers of lactic acid, as probiotics, as biocontrol agents and as biopreservatives. LAB play a large role in food fermentation and in silage processes, where crops such as grass, legumes, cereals or corn are fermented into high-moisture feed that is storable and can be used to feed cattle, sheep or other ruminants. LAB also have great applications within green biorefineries, with simultaneous production of protein-rich feed for monogastric animals, silage or feed pellets for ruminants and production of lactic acid or specific amino acids. In green biorefineries, fresh or ensiled wet biomass is mechanically fractionated into green juice and solid residues (press cake), where the plant juice, for example, can be used for production of lactic acid using LAB. In a process named 'ENLAC', recovery of protein and chlorophyll from silage by simultaneous lactic acid fermentation and enzyme hydrolysis has been developed. Furthermore, a process for protein recovery was recently developed by applying a specific LAB starter culture to green juice from freshly harvested crops. This paper focuses on reviewing LAB for their applications within biorefining of 'green' crops such as clover, alfalfa, grasses and other green plant materials.

Comparison of the functional properties of RuBisCO protein isolate extracted from sugar beet leaves with commercial whey protein and soy protein isolates

BACKGROUND

RuBisCO was extracted from sugar beet leaves using soft and food-compatible technologies. Proximate composition, solubility, emulsifying, foaming and gelling properties of the protein isolate were determined. All these properties were systematically benchmarked against commercial whey and soy protein isolates used in food applications.

RESULTS

RuBisCO protein isolate (RPI) contained 930 g kg^-1 of crude protein. Protein solubility was higher than 80% at pH values lower than 4.0 or higher than 5.5. Foaming capacity of RPI was better at pH 4.0 than at pH 7.0. Interestingly, 10 g kg^-1 protein foams were more stable (pH 7.0 and 4.0) than foams obtained with whey or soy protein. Moreover, 10 g kg^-1 RPI emulsions at pH 4.0 or 7.0 exhibited good stability, being similar to whey protein isolate. Remarkable gelling properties were observed at pH 7.0, where 50 g kg^-1 protein solutions of RPI formed self-supporting gels while more concentrated solutions were needed for whey or soy protein.

CONCLUSION

RuBisCO showed comparable or superior functional properties to those of currently used whey and soy protein isolates. These results highlight the high potential of sugar beet leaf protein isolate as a nutritious and functional food ingredient to face global food security and protein supply. © 2018 Society of Chemical Industry.

Food Proteins: Technological, Nutritional, and Sustainability Attributes of Traditional and Emerging Proteins

Protein is an essential macronutrient and a key structural component of many foods. The nutritional and technological properties of food protein ingredients depend on their source, extraction and purification, modification during food manufacture, and interactions with other food components. In addition to covering these elements, this review seeks to highlight underappreciated aspects of protein environmental sustainability and explores the potential of cultured meat and insect-derived proteins.

Bio-Based Products from Microalgae Cultivated in Digestates

In recent years the increasing demand for food, energy, and valuable chemicals has necessitated research and development on renewable, novel, and sustainable sources. Microalgae represent a promising option to produce various products with environmentally friendly applications. However, several challenges must be overcome to reduce production cost. To this end, using effluents from biogas production units, called digestates, in cultivation systems can help to optimize bioprocesses, and several bioproducts including biofuels, biofertilizers, proteins and valuable chemicals can be obtained. Nevertheless, several parameters, including the productivity and quality of biomass and specific target products, downstream processes, and cost-effectiveness, must be improved. Further investigations will be necessary to take full advantage of the produced biomass and effectively upscale the process.