For the investigation of retention and release of flavor components, various methods are available, which are mostly used on a case-to-case basis depending on the raw material. These effects that originate from kinetics and thermodynamics could be put in a much wider perspective if these fields were taken as a starting point of investigation in combination with rigorous data analysis. In this Review, we give an overview of experimental techniques and data analysis methods, and predictive methods using mass transfer techniques are also discussed in detail. We use this as a foundation to discuss the interactions between volatile flavors and the matrix of liquid foods/beverages. Lipids present in the form of an emulsion are the strongest volatile retainers due to the lipophilic nature of most of the volatile flavors. Proteins also have flavor retention properties, whereas carbohydrates hardly have a retention effect in beverages. Smaller components, such as sugars and salts, can change the water activity, thereby facilitating flavor release. Alternatively, salts can also indirectly affect binding sites of proteins leading to release (e.g., NaCl and Na2SO4) or retention (NaCSN and Cl3CCOONa) of flavors. Furthermore, the effects of temperature and pH are discussed. The Review concludes with a critical section on determination of parameters relevant to flavor release. We highlight the importance of accurate determination of low concentrations when using linearization methods and also show that there is an intrinsic preference for nonlinear regression methods that are much less sensitive to measurement error.

For alcoholic beverages such as beer, downstream processing for either dealcoholization or off-flavor removal requires both quantitative data and suitable predictive methods. Along with experimental investigations, we use a method initially developed for studying the solubility of gases in two or more miscible liquid solvents to monitor the effect of ethanol on air–water partition coefficients of three major flavors found in beer, namely, isoamyl alcohol, ethyl acetate, and isoamyl acetate. In the ethanol concentration range between 0 and 0.1 mole fraction, a slight, rather linear increase in the Henry’s solubility coefficient was observed. This overall behavior can be captured well using Henry coefficients for aqueous binary and ternary systems together with the Wohl expansion for excess Gibbs free energy coupled with the one-parameter Margules equation. Based on the developed model, the Wohl’s expansion parameter for ethanol–water is introduced as the solvent–solvent interaction parameter. The van ’t Hoff parameters for temperature dependence of Henry coefficients for binary water–flavor solutions are determined in the range of 30 to 60 °C.

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Background Evidence is growing for the efficacy of platelet-rich plasma (PRP) in knee osteoarthritis (OA). Here, we investigated the effects of PRP and placebo by performing a randomized, double-blind, within-person between knees comparison of measurements.Methods Thirty patients with equal radiographic grades of OA in both knees received a single injection of PRP in one knee and normal saline as a placebo in the contralateral knee. Knee symptoms were assessed at baseline and at 6-week follow-up using the WOMAC (Western Ontario and McMaster Universities) Osteoarthritis Indices for pain, stiffness, and physical function and the pain visual analog scale (VAS) assessments.Results The VAS-pain and the mean WOMAC subscales- pain, stiffness, and function- decreased significantly (P = 0.001, 0.005, 0.024, and 0.005, respectively) from baseline to week 6 in the PRP-injected knees, while in the placebo-injected knees there were only a significant reduction of VAS and no difference in WOMAC outcomes. Intergroup comparison of pain-VAS and WOMAC sub-scales revealed no statistically significant differences between PRP- and placebo-treated knees of patients post-injection.Conclusion This study found little difference between the effects of intra-articular PRP injection and placebo when applied to the same patient. Non-significant improvement in osteoarthritis indices between the treatment and placebo-received knees indicate the need for additional clinical trials of crossover design.Trial registration: IRCT2016030626922N1

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