Increased significance of food wastes: Selective recovery of added-value compounds

Abstract

A single-step selective separation of two food additives was investigated using alcohol-salt aqueous two-phase systems (ATPS). The selective partitioning of two of the most used additives from a processed food waste material, vanillin and l-ascorbic acid, was successfully accomplished. The results obtained prove that alcohol-salt ATPS can be easily applied as cheaper processes for the selective recovery of valuable chemical products from food wastes and other sources. As a first approach, the phase diagrams of ATPS composed of different alcohol+inorganic salt+water were determined at 298 (± 1)K and atmospheric pressure. The influence of methanol, ethanol, 1-propanol, and 2-propanol and K(3)PO(4), K(2)HPO(4) or KH(2)PO(4)/K(2)HPO(4) in the design of the phase diagrams was addressed. After the evaluation of the phase diagrams behaviour, the influence of the phase forming constituents was assessed towards the partition coefficients and recovery percentages of vanillin and l-ascorbic acid among the coexisting phases. Both model systems and real processed food waste materials were employed. Using these ATPS as partitioning systems it is possible to recover and separate vanillin, which migrates for the alcohol-rich phase, from l-ascorbic acid, which preferentially partitions for the salt-rich phase.

Extraction and Recovery of Rutin from Acerola Waste using Alcohol-Salt-Based Aqueous Two-Phase Systems

“…Previously, we have published (32) the pH values of the coexisting phases of the systems studied here. For the systems composed of K 3 PO 4 the media is highly alkaline, with pH values ranging between 12.38 and 13.22, while the pH values for the remaining systems are lower and closer to the pKa of rutin.…”

“…Despite these conventional ATPS, more recent works have shown the possibility of forming liquid-liquid systems by the combination of an organic solvent and a salt (32) or by the addition of an inorganic salt to an aqueous ionic liquid solution (33,34). Particularly, the use of polymer-polymer and polymer-salt systems has some disadvantages, such as the high cost of the polymer, phases of high viscosity, a slow phase separation, and a challenging recyclability of the phase forming components (35).…”

Application of an ultrasound process to extract catechins from green tea wastes

“…Estes são, porém, uma incrível fonte de matérias-primas ou de substâncias de valor, e há, portanto, a necessidade de desenvolver novas tecnologias de recuperação de reutilização a fim de retirar valor agregado destes compostos que são descartados como resíduos (REIS et al, 2012).…”

Aqueous two-phase systems based on cholinium salts and tetrahydrofuran and their use for lipase purification

“…However, their performance is significantly affected due to the small difference in polarity between the coexisting phases [18]. Currently, the number of systems capable of forming two aqueous phases is increasing and the alternatives include the use of alcohol/salt [19][20][21], acetonitrile/carbohydrates [22,23], polymers(polyvinyl alcohol -PVA)/dextran [24] and other combinations including ionic liquids (ILs) [25,26]. The numerous combinations of cations and anions that form ILs lead to a variety of physical properties, allowing the tailoring of their polarities, and for this reason have been regarded as important constituents of ATPS [27][28][29].…”