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Evaluation of quality and potential bioactive of fruit drinks : application of spectroscopy on infrared and chemometric

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Elem Tamirys dos Santos Caramês
Total Authors: 1
Document type: Master's Dissertation
Defense date:
Advisor: Juliana Azevedo Lima Pallone

Brazil is the third largest producer of fruits in the world. Among the fruits produced in the national territory, cashew apple (2 million tons / year), guava (345,000 tons / year) and grapes (1.4 million tons / year), are noteworthy for the great production and variety of products generated from them (juices, nectars, squashes, jams, soft drinks, etc.). The beverage industry, juices and nectars, has been responsible for the movement of US $ 1.9 billion from the sale of 476 million liters/ year, this share of the market has been driven by consumers looking for healthier products. Nectars of cashew apple and guava, present high content of vitamin C found in fruits (average 230 mg/100g and 600 mg/100g, respectively) and grape juice has a significant amount of phenolic compounds, especially anthocyanins. Ascorbic acid, phenolic compounds, including anthocyanins are labile compounds and subject to oxidative degradation, especially in aqueous media, such as drinks. To ensure the quality of nectars Brazilian legislation defined acidity parameters (TA) and total sugars (TS), soluble solids (SS), pH and ascorbic acid (AA) that are commonly performed by traditional analyzes involving the use of toxic substances, danger to the analyst and the environment, and the need for specific equipment. Similar scenario is found to analyze concentration of total phenolics content (TPC) and anthocyanins content (TAC) of grape juice, with the aggravation that these analyzes, in general, are time consuming and therefore impair the stability of the bioactive compounds during the process. As an alternative to these problems, this work proposes to use the spectroscopic analysis NIR and/or MIR along with chemometrics as an alternative to analyze nectars cashew and guava (ACT, AT, SS, pH and AA) and grape juice (TF and TA), to replace the traditional analysis. The spectra obtained by transflectance were preprocessed to reduce multiplicative effects (MSC/SNV), to improve signal/noise ratio (smoothing using Savitzky-Golay), baseline correction (derived by Savitzky-Golay) and mean centered. Among the PLS calibration models constructed for the analyzes in nectars stood out the AA model for cashew¿s nectar (RMSEP= 4.8 mg/100g and RMSEC= 4.6 mg/100g) and AT for guava¿s nectar (RMSEP = 0.315% and RMSEC = 0.297%), the other models presented good values of R² (> 0.7) in addition to low values of RMSEP and RMSEC. Calibration models using NIR and MIR constructed to determine TA and TF in grape juice showed similar performance. MIR and NIR models for TA forecast RMSEP had low values (4,22mg / 100mL and 4,44mg / 100 mL, respectively) and for predicting TF, MIR presented a slightly smaller RMSEP than presented by NIR (2.12 EqAGmg/ml and 3.71 EqAGmg/mL, respectively). The RMSEP values found for all models built in this work show that spectroscopic analysis, NIR and MIR, can act as a substitute for traditional analyzes for quality control nectars and bioactive compounds in grape juice, with the advantages of being chemically green, fast and efficient, and do not require sample preparation, avoiding errors due to instability of the compounds evaluated (AU)

FAPESP's process: 15/15848-0 - Development of calibration models using NIR for evaluate adulteration and physical-chemical properties of whole UHT liquid milk and investigation of quality and antioxidant capacity of nectars and fruit pulps
Grantee:Juliana Azevedo Lima Pallone
Support type: Regular Research Grants