Peach Purees Research Articles

Combined Analysis of Primary Metabolites and Phenolic Compounds to Authenticate Commercial Monovarietal Peach Purees and Pear Juices.

Here we authenticated single-varietal peach purees and pear juices on the basis of primary metabolite and phenolic compound analysis by Proton Nuclear Magnetic Resonance (1H-NMR) and Ultra Performance Liquid Chromatography coupled to Photodiode Array and Tandem Mass Spectrometry (UPLC-PDA-MS/MS), respectively. After suitable preprocessing, the 1H-NMR and chromatographic data were evaluated by principal component analysis (PCA). The PCA combining data from primary metabolites and phenolic compounds allowed the separation of the clusters in all cases, allowing discrimination of processed and unprocessed peach purees, both separately and pooled. The PCA of primary metabolites allowed the cluster separation of purees of distinct peach varieties but not between processed and non-processed purees. The PCA of phenolic compounds allowed better cluster separation than of primary metabolites. For pear juices, both PCA approaches allowed satisfactory discrimination of Alejandrina, Conference, and Blanquilla cultivars. These approaches may help to better control cultivar authenticity in fruit products. It could therefore contribute to the development of a process to achieve products characterized by a quality characteristic of a given cultivar.

Characterization of polyphenols in apricot and peach purees by UHPLC coupled to HRMS Q-Exactive(™) mass spectrometer: an approach in the identification of adulterations.

The genuineness of fruit juices and purees is regulated by guidelines of European Fruit Juice Association. Nevertheless, the addition of peach puree to apricot puree is considered the most common adulteration, very difficult to discover. In this study, the composition in free and conjugated polyphenols of apricot and peach purees was performed by target and untarget approaches with Q-Exactive(™) quadrupole-Orbitrap mass spectrometer. Apricot purees showed a higher polyphenol content than those of peaches. Between target coumpounds, chlorogenic acid, rutin, catechin and smaller quantities of hyperoside and kaempferol-3-rutinoside were found in both purees. Apricot puree was also found to contain epicatechin and procianidin B2, absent in peach puree. Peach puree was found to contain small amounts of kaempferol-3-glucoside, absent in apricot. In order to identify untarget polyphenols, data obtained by ultra-high pressure liquid chromatography tandem mass spectrometry analysis were processed with Thermo Scientific automated label-free differential expression software (sieve(™) 2.1 software). Three hydroxycinnamic acid conjugates and a procyanidin were identified and confirmed by tandem mass spectrometry spectra. Some compounds of interest found from differential analysis had a putative identification, while others remained unidentified. The high-resolution mass spectrometry approach using Q-Exactive(™) quadrupole-Orbitrap mass spectrometer could be an important and powerful tool for determination of new biomarkers in fruits and vegetables. Copyright © 2016 John Wiley & Sons, Ltd.

RHEOLOGICAL CHARACTERIZATION OF PEACH PUREES

ABSTRACT In this work, two commercial peach purees (21 and 11.9°Brix) industrially obtained have been studied at several temperatures involved in industrial processes. Viscoelastic functions were that of a weak gel, and decreased with temperature and increased with concentration. Rheograms were obtained in order to determine the yield stress, which is related to stability against settling during storage. Herschel–Bulkley equation was used to determine the consistency index and the flow index. Thixotropy was quantified by means of one empirical equation (Weltmann model) and two theoretical equations (Figoni–Shoemaker and Tiu–Boger models), which describe the first‐ and second‐order kinetic process of structure breakdown. Both peach purees show thixotropy under nonsteady conditions. The broken‐down structure increased with the applied shear rate and, practically, decreased as the temperature was increased for both peach purees. The breakdown kinetic constants decreased as the shear rate was increased for both theoretical equations following a power law dependency. PRACTICAL APPLICATIONSIt is necessary to know the thixotropic behavior of peach purees, since knowledge of the rheological properties is very important in order to improve the design, manipulation and calculation of all those unit operations during the process (i.e., agitation and filtration) and design equipment (i.e., pump systems and pipe sizing), mainly those based on heat and quantum transfer.

Um estudo para compreender a preferência e aceitação de consumidores de purês de pêssegos brasileiros

Testes de preferência e de aceitação foram realizados para determinar a relação entre parâmetros e atributos de qualidade de purês de pêssegos elaborados a partir das cvs. Granada, Jade, Esmeralda, Maciel, Eldorado, Jubileu, Br-6 e Magno. Pêssegos da safra 2003-2004 foram colhidos em pomar comercial na região de Pelotas - RS. As propriedades físicas e químicas foram determinadas com quatro repetições de vinte pêssegos de cada cultivar. O purê de pêssego foi elaborado por branqueamento contínuo. Os testes de preferência e aceitação foram aplicados com 50 consumidores, e as respostas dos consumidores foram registradas, respectivamente, em uma escala auto-ajustável e uma hedônica de nove pontos. Também, utilizou-se um teste descritivo com nove julgadores treinados. Analisaram-se os resultados por ANOVA, e as diferenças significativas, pelo teste de Tukey. As oito cultivares selecionadas variaram amplamente em suas características físicas e químicas. De modo geral, o teor de fenóis incrementou com o ciclo de colheita, e as cultivares Eldorado, BR-6, Jubileu e Magno foram superiores para relação SS/AT (e" 15,1), que é considerado um bom indicador para fruta de alta qualidade. Os purês elaborados com as cultivares Jubileu e Eldorado foram os preferidos pelos consumidores. O principal motivo dessa escolha foi o equilíbrio existente entre ácido e doce, que foi significativamente relacionado com SS/AT. As cultivares com baixo conteúdo de fenóis totais, quando manufaturadas, resultaram em purês de pêssegos de coloração amarela, que é uma característica desejável.

Temperature dependent electrical conductivities of fruit purees during ohmic heating

Ohmic heating takes its name from Ohm’s law; the food material switched between electrodes has a role of resistance in the circuit. In this study, the apricot and peach purees were heated on a laboratory scale static ohmic heater by applying voltage gradients in the range of 20–70 V/cm. The voltage gradient was statistically significant on the ohmic heating rates for both purees ( P < 0.05). The linear temperature dependent electrical conductivity relations were obtained. Bubbling was observed above 60 °C especially at high voltage gradients. The ohmic heating system performance coefficients were in the range of 0.49–1.00. The unsteady-state heat conduction equation for negligible internal resistance was solved with an ohmic heating generation term by the finite difference technique. The predictions of the mathematical model using obtained electrical conductivity equations were found to be very accurate.

HIGH HYDROSTATIC PRESSURE PROCESSING OF PEACH PUREE WITH AND WITHOUT ANTIBROWNING AGENTS

High hydrostatic pressure (HHP) (103 to 517 MPa) was applied for selected times (5 to 25 min) on peach puree with and without the addition of antibrowning agents (1000 ppm ascorbic acid or 300 ppm cysteine). Polyphenoloxidase (PPO) activity was assessed before and after HHP processing. Peach purees were stored at 3C for 13 days and then at 22C for 15 additional days. A zp value of 224 MPa, in a range from 207 to 517 MPa of pressure, was obtained for peach puree without the addition of antibrowning agents. PPO activation at 103, 207 and 310 MPa or inhibition at 414 and 517 MPa was observed in peach purees containing added ascorbic acid. More than 50% inactivation of PPO was observed after adding cysteine to the peach puree and 99% inhibition was observed after 517 MPa of pressure at the experimental times. The higher the pressure treatment and the longer the treatment time for inactivating PPO, the less the discoloration of the peach puree with and without antibrowning agents during storage at low temperatures.

Flow Characterization of Peach Products During Extrusion

ABSTRACT:Suitability of Bingham, Herschel‐Bulkley, Casson, and Mizrahi‐Berk models, to characterize the flow behavior of peach products during extrusion was investigated. The Casson equation sufficiently described the flow of peach extrudates within the 49 to 125 s‐1 shear rate range. As concentration increased, yield stress and consistency coefficients increased. A rheological model was proposed to describe the viscosity of peach extrudates. The model incorporates the effect of shear rate by the Casson equation and the effect of concentration by a linear expression. The model provided good fit to the experimental data for peach extrudates reconstituted from drum‐dried peach purees.

The Role of Trichosporon cutaneum in Eliciting Aggregation Behavior in Cotinis nitida (Coleoptera: Scarabaeidae)

Aggregation behavior was elicited in both sexes of the green June beetle, Cotinis nitida (L.), when green June beetle males fed on peach slices inoculated with one yeast species, Trichosporon cutaneum (de Beurm. Gougerot et Voucher) Ota. Peach puree monocultures were made by inoculating sterile peach puree with one of three yeasts ( Aureobasidium pullulans (de Bary) Arnaud, Candida krusei (Castellani) Berkhout, C. tropicalis (Castellani) Berkhout), which were all endemic flora isolated from the feces and gut of green June beetles collected from feeding aggregations on unsterile peaches in the field (natural bait). In a field bioassay, peach puree monocultures of C. tropicalis (in experiment A) and C. krusei (in experiment B), both without beetle feeding, were significantly more attractive ( P < 0.05) to both sexes of green June beetles than sterile peach puree with or without beetle feeding, but all peach purees were significantly less attractive than the most attractive natural bait. In experiment C, peach slices were inoculated with either of two yeasts (biovars A or B of T. cutaneum ), which were the predominant isolates from the gut of laboratory-reared green June beetles fed on unsterile peaches. These monocultures of T. cutaneum on peach slices without beetle feeding were relatively as attractive as monoculture-inoculated peach puree alone containing one of the three other yeasts noted above. But when laboratory-reared green June beetle males previously fed on the T. cutaneum -inoculated peach slices were included with these peach slices, the bait containing biovar A was as attractive as the natural bait. Although the bait of laboratory-reared green June beetle males feeding on peach slices inoculated with biovar B was significantly less attractive ( P < 0.05) than the natural bait, it was Similarly attractive to the laboratory-reared green June beetle males feeding on the biovar A-inoculated peach slices. The laboratory-reared green June beetles required a period of 1 d or more of feeding on yeast-inoculated fruit to achieve peak production of aggregation semiochemical.

Chemistry of non-enzymic browning. II. Reactions between Amino Acids, Organic Acids, and sugars in freeze-dried Apricots and Peaches

The water-soluble constituents of apricot and peach purees were examined qualitatively and quantitatively before and after storage for 4 to 16 months at 25 �C and 70 per cent. R.H. All samples contained all the amino acids, organic acids, sugars, and polyols previously detected (Reynolds 1967 ; Anet and Reynolds 1955a, 1966b ; Ash and Reynolds 1955a, 1955b) in the two species of fruit. The stored samples also contained the following compounds : eleven 1-(N-amino acid)-1-deoxyfructoses, traces of two 2-(N-amino acid)-2-deoxyglucoses, nine by-products of unknown constitution formed from the reaction between glucose and aspartic acid and glucose and asparagine, three compounds formed from ammonia and glucose, two series of sucrose, glucose, and fructose mono-esters of malic acid, traces of a sorbitol mono-ester of malic acid, and some sugar mono-esters of citric acid.�The free amino acid or organic acid lost was equal, on a molar basis, to the amino acid-deoxyfructoses (and related compounds) and sugar esters formed. After allowing for these derivatives as much as 7 per cent. of the total sugar (calculated as hexoses) originally present could not be accounted for.