A critical review of methods for characterisation of polyphenolic compounds in fruits and vegetables.

Supercritical extraction and fractionation of natural matter is one of the early and most studied applications in the field of supercritical fluids In the last 10 years, studies on the extraction of classical compounds like essential and seed oils from various sources: seeds, fruits, leaves, flowers, rhizomes, etc, with or without the addition of a co-solvent have been published Supercritical extraction of antioxidants, pharmaceuticals, colouring matters, and pesticides has also been studied The separation of liquid mixtures and the antisolvent extraction are other processes that can perform very interesting separations Mathematical modelling has also been developed and refined for some of these processes The objective of this review is to critically analyze traditional and new directions in the research on natural matter separation by supercritical fluids extraction and fractionation

Supercritical fluid extraction and fractionation of natural matter

Phenolic compounds are well-known phytochemicals found in all plants. They consist of simple phenols, benzoic and cinnamic acid, coumarins, tannins, lignins, lignans and flavonoids. Substantial developments in research focused on the extraction, identification and quantification of phenolic compounds as medicinal and/or dietary molecules have occurred over the last 25 years. Organic solvent extraction is the main method used to extract phenolics. Chemical procedures are used to detect the presence of total phenolics, while spectrophotometric and chromatographic techniques are utilized to identify and quantify individual phenolic compounds. This review addresses the application of different methodologies utilized in the analysis of phenolic compounds in plant-based products, including recent technical developments in the quantification of phenolics.

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Techniques for analysis of plant phenolic compounds.

https://digital.csic.es/bitstream/10261/22454/3/SUPERCRITICAL%20FLUID%20EXTRACTION.pdf

Supercritical fluid extraction: Recent advances and applications

This review presents innovative food processing techniques and their role in promoting sustainable food industry. These techniques (such as microwave, ultrasound, pulse electric field, instant controlled pressure drop, supercritical fluid processing) in the frontiers of food processing, food chemistry, and food microbiology, are not new and were already used for> 30 years by academia and industry. We will pay special attention to the strategies and the tools available to make preservation, transformation and extraction greener and present them as success stories for research, education and at industrial scale. The design of green and sustainable processes is currently a hot research topic in food industry. Herein we aimed to describe a multifaceted strategy (innovative technologies, process intensification, bio-refinery concept) to apply this concept at research, educational, and industrial level.
Industrial relevance: Green Food Processing could be a new concept to meet the challenges of the 21st century, to protect both the environment and consumers, and in the meantime enhance competition of industries to be more ecologic, economic and innovative. This green approach should be the result of a whole chain of values in both senses of the term: economic and responsible, starting from the production and harvesting of food raw materials, processes of preservation, transformation, and extraction together with formulation and marketing.

https://hal.archives-ouvertes.fr/hal-01552142/document

Review of Green Food Processing techniques. Preservation, transformation, and extraction

This work describes an innovative process for the extraction of lycopene from tomato using supercritical carbon dioxide in the presence of vegetable oil as co-solvent. The presence of the co-solvent improves the yields of the lycopene extract and has a beneficial role in the stability of the pigment. A complete description of the extraction process is also reported. The experiments carried out with and without co-solvent at pressures and temperatures ranging from 335 to 450 bar and 45 to 70 °C, respectively, bar have shown that the amount of the extractable lycopene depends on the experimental conditions. Also, the maximum amount of the extractable lycopene from dried tomato (6% of moisture, average particle size of about 1 mm), at 450 bar and 66 °C in the presence of co-solvent and utilizing a flow rate of about 20 kg CO 2 /h, was 60%. The extracts were analyzed by high-performance liquid chromatography and UV–vis spectra.

Innovative supercritical CO2 extraction of lycopene from tomato in the presence of vegetable oil as co-solvent

An innovative method for the purification of anthocyanins from grape skin extracts by using liquid and sub-critical carbon dioxide

The objective of this study was to extract oil and tocopherols from almond seeds using supercritical carbon dioxide and to compare this extraction with a traditional solvent method. Oil and tocopherol extraction rates were determined as functions of the pressure (350-550 bar), temperature (35-50 ◦ C) and CO2 flow rate (10-30 kg h −1 ), using a 10-l vessel. The effects of matrix particle size on extraction yield were also studied and it was demonstrated that extraction yield is greatly influenced by particle size. Maximum recovery was obtained in the first 2-3 h of extraction at a pressure of 420 bar, a temperature of 50 ◦ C and a flow rate of 30 kg h −1 CO2. These results suggest that the elevated initial oil and tochopherol solubility is related to the increased proportion of fatty acids in the initial extract. The results were compared with those obtained when hexane/methanol was used as a solvent.  2005 Society of Chemical Industry

Supercritical carbon dioxide extraction of oil and α‐tocopherol from almond seeds

An innovative SC-CO2 procedure for lycopene extraction from a matrix, composed by a mixture of dried tomatoes (pulp and skins without seeds) and roasted hazelnuts, is here described. The supercritical fluid simultaneously extracted oil from hazelnuts and lycopene from tomatoes, dissolving the pigment into the oil (temperature of 60 °C, pressure of 400 bar, flow rate of 10 kg CO2/h). The extraction yields were: 72.5% for lycopene, 80% for hazelnut oil. The final product was an over-saturated solution of lycopene in hazelnut oil, characterized in terms of concentration and isomeric composition of lycopene. A centrifugation-based procedure allowed to obtain a pasty extract, in which lycopene was five-fold more concentrate than the starting solution (4.12% vs. 0.74%, w/w). This protocol allowed to obtain the separation of lycopene isomeric forms: all-trans lycopene was collected as precipitate, cis-lycopene remained in solution in the oil phase.

Supercritical carbon dioxide co-extraction of tomatoes (Lycopersicum esculentum L.) and hazelnuts (Corylus avellana L.): A new procedure in obtaining a source of natural lycopene

COSMECEUTICALS JULY/AUGUST 2005 23 NutraCos A large number of natural compounds may often represent the solution for a wide number of problems in human health. In fact, their pharmaceutical activities detain a large range of action, i.e. from the active ingredients against the most serious diseases to the molecules able to reduce the slight blemish (1). Plant extracts have been used for healing purposes long before recorded history, as demonstrated by ancient Chinese and Egyptian papyrus writings describing medicinal plant uses. Several African populations used plants in their curative rituals, while others, such as indigenous populations of North America, developed traditional medical systems in which herbal therapies were used systematically (2,3). At the present time, people in different parts of the globe use plant seeds, berries, roots, leaves, bark, or flowers for the same purposes. In the early 19th century, when methods of chemical analysis became available, scientists began to extract and to study several active ingredients from plants. A wide number of active products deriving from plant extracts have been included into nutritional supplements and used to correct imbalances, resolve patterns of dysfunction and treat the cause of complaint. Several molecules have been extracted and used to treat many human pathologies such as asthma, eczema, premenstrual syndrome, rheumatoid arthritis, migraine, menopausal symptoms, chronic fatigue and irritable bowel syndrome (4). The nutritional supplements have been termed as Nutraceuticals, as they are defined as “a category of substances that may provide medical or health benefits, including prevention and treatment of disease” (5). As the consumption of nutritional supplements and the improvement of lifestyle require time to show their effects, nowadays, consumers express an increasing request of immediate benefits complementary to Nutraceuticals. To support this need of new molecules and systems to obtain the desired short-term benefits, the cosmetic industry has recently developed combinations of cosmetic formulations enriched with pharmaceutical compounds, thus new categories of products have been developed, denoted Cosmeceuticals (6).

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Loredana Ciurlia

Papers

Innovative supercritical CO2 extraction of lycopene from tomato in the presence of vegetable oil as co-solvent

An innovative method for the purification of anthocyanins from grape skin extracts by using liquid and sub-critical carbon dioxide

Supercritical carbon dioxide extraction of oil and α‐tocopherol from almond seeds

Supercritical carbon dioxide co-extraction of tomatoes (Lycopersicum esculentum L.) and hazelnuts (Corylus avellana L.): A new procedure in obtaining a source of natural lycopene

Supercritical carbon dioxide extracts from red fruits: A "natural" cosmeceutical application