Phenolic, sugar and acid profiles and the antioxidant composition in the peel and pulp of peach fruits

Unlocking peach juice byproduct potential in food waste biorefineries: Phenolic compounds profile, antioxidant capacity and fermentable sugars

This work assesses an integrated pathway for the revalorization of peach byproduct (PB) within a biorefinery. PB was subjected to an oven-drying (OD) treatment for its evaluation as a storage treatment. It was compared to freeze-drying and untreated material in terms of antioxidant capacity (AOC), phenolic compounds (PC) profile and fermentable sugar production. OD reduced the water content to less than 15 % while preserving the bound hydrolysable polyphenols, which were the more abundant PC (≈64 %) with the highest AOC. Drying treatments hampered polysaccharide accessibility, but some enzyme preparations released 60-70 g/L of fermentable sugars at relatively high solids loading (10 %). This study proposes a novel enzyme-based strategy for the valorisation of fermentable sugars and antioxidant compounds from PB. The sugars can be fermented into several building blocks while the solid residue enriched in recalcitrant phenolic compounds and proteins could be used to develop novel functional products for food/feed sectors.

Main flavor compounds and molecular regulation mechanisms in fruits and vegetables

Fruits and vegetables (F&V) are an indispensable part of a healthy diet. The volatile and nonvolatile compounds present in F&V constitute unique flavor substances. This paper reviews the main flavor substances present in F&V, as well as the biosynthetic pathways and molecular regulation mechanisms of these compounds. A series of compounds introduced include aromatic substances, soluble sugars and organic acids, which constitute the key flavor substances of F&V. Esters, phenols, alcohols, amino acids and terpenes are the main volatile aromatic substances, and nonvolatile substances are represented by amino acids, fatty acids and carbohydrates; The combination of these ingredients is the cause of the sour, sweet, bitter, astringent and spicy taste of these foods. This provides a theoretical basis for the study of the interaction between volatile and nonvolatile substances in F&V, and also provides a research direction for the healthy development of food in the future.

Eating with peel or not: Investigation of the peel consumption situation and its nutrition, risk analysis, and dietary advice in China

Nutritious, balanced, tasty and easy to eat, fruit is an indispensable health food for consumers. With consumers' increasing respect for the concept of health, green and nutrition, the peel, which has higher nutritional value compared to the pulp, is gradually being emphasized in the consumption process. The suitability of fruit peels for consumption is influenced by various factors, such as the amount of pesticide residues, nutrient content, ease of peeling, and fruit texture, but there is a lack of relevant studies to guide consumers' scientific intake of fruit peels. This review first investigated chineses consumers consumption of common fruits with peels, especially eight fruits that are controversial in terms of whether to consume them with peels, and the results showed that whether people consume peels depends mainly on their nutritional value and pesticide residues. Based on this, the paper discusses the common methods of pesticide detection and removal from fruit peels, as well as the nutrients contained in different fruit peels and their physiological activities, if the peels usually have stronger antioxidant, anti-inflammatory and anti-tumor activities than the pulp. Finally, reasonable dietary recommendations are made on whether fruits should be consumed with their peels, with a view to guiding chineses consumers towards scientific consumption and provide theoretical basis for relevant research in other countries.

Evaluation of the Fruit Quality and Phytochemical Compounds in Peach and Nectarine Cultivars

Qualitative traits and chemical properties of 32 peach cultivars (yellow flesh and white flesh fruits) and 52 nectarine cultivars (yellow flesh and white flesh fruits) of different pomological characteristics is performed, and the correlation between cultivars and chemical characteristics is analyzed. Yellow nectarines have a higher variability in soluble solids concentration (SSC) and titratable acidity (TA) values. Evaluation of color parameters (a*, b*, L*) shows a significant interaction between pulp color (white vs. yellow) and types (peaches vs. nectarines) of fruit. The difference between yellow and white fruits is stronger in nectarines than in peaches. Sucrose is the main sugar detected in peach fruits, with a percentage content of 78.37% and 76.70% of the total sugar content in yellow and white peaches, respectively, and 78.29% and 78.12% in yellow and white nectarines, respectively. Variability is found among cultivars for the chemical compounds analyzed. The yellow flesh has higher amounts of total carotenoids and TPC, while white-flesh fruits present an average antioxidant value higher than yellow-flesh fruits. No significant correlation is found for polyphenol content and DPPH, while an interaction (p < 0.005) between neochlorogenic acid content and peaches and nectarines is evidenced, with a neochlorogenic acid content higher in nectarines than in peaches.

Quantitative and qualitative determination of carotenoids and polyphenolics compounds in selected cultivars of Prunus persica L. and their ability to in vitro inhibit lipoxygenase, cholinoesterase, α-amylase, α-glucosidase and pancreatic lipase

The present study aimed to evaluate the content of polyphenols and carotenoids as well as the health-promoting properties (antioxidant, antidiabetic, antiobesity, antiaging, and anti-inflammatory activities) in selected peaches cultivated in Poland. The qualitative analysis of the tested cultivars showed that the content of polyphenols was dominated by flavan-3-ols, and phenolic acids. In turn, the performed analysis clearly indicated that the dominant carotenoid was β-carotene, which constituted on average 88% of the total amount of carotenoids. The general content of yellow pigments is as follows: all-trans-β-carotene > 13 cis-β-carotene > 9 cis-β-carotene > zeaxanthin > β-cryptoxanthin ≥ β-cryptoxanthin-myristate > β-cryptoxanthin-palmitate > crocin ≥ cis-violaxanthin > lutein. In addition, the present study showed that the peach fruit has a high potential in the context of inhibition of pancreatic lipase, which may indicate a potential antiobesity effect. However, the potential of the peaches to inhibit α-amylase, α-glucosidase, or 15-LOX has not been demonstrated.

Prunus lusitanica L. Fruits: A Promising Underexploited Source of Nutrients with Potential Economic Value

In recent times, less-known fruit species have increasingly attracted worldwide attention and their health benefits are at the forefront. The fruits of plants from the genus Prunus are good sources of nutrients due to their economic, agronomic, and healthy values. However, Prunus lusitanica L., commonly known as Portuguese laurel cherry is considered an endangered species. Thus, the present work aimed to monitor the nutritional components of P. lusitanica fruits grown in three locations in northern Portugal for four consecutive years (2016-2019), using AOAC (Association of Official Analytical Chemists), spectrophotometric, and chromatographic analysis. The results evidenced the abundance of phytonutrients in P. lusitanica, such as proteins, fat, carbohydrates, soluble sugars, dietary fibre, amino acids, and minerals. It was also highlighted that the variation of nutritional components was relatively linked to the year factor, being especially relevant in the frame of the current changing climate, among others. These findings suggest that P. lusitanica L. deserves to be conserved and planted because of its food and nutraceutical applications. However, more detailed information on this rare plant species, such as phytophysiology, phytochemistry, bioactivity, pharmacology, etc., is certainly required for the design and development of appropriate uses and valorization alternatives for this species.

A strategy for healthy eating habits of daily fruits revisited: A metabolomics study

Many people peel fruits, commonly persimmon, grape, apple, and peach, before eating as table fruits. Differences of bioactive compounds between peels and pulps of daily fruits are widely known but limited to individual compound because understanding of differences in their global metabolites is lack. We employed ¹H NMR-based metabolomics to explore the global metabolite differences between their peels and pulps from the fruits, which included changes of diverse metabolites in persimmon after harvest ripening. Of diverse metabolites observed among the fruits tested, various health-beneficial metabolites were present in the peels rather than the pulps and their classes were dependent on the type of fruit: gallocatechin, epicatechin and epigallocatehin only in persimmon, apple, and peach, respectively; quercetin only in persimmon and apple; kaempferol only in persimmon; chlorogenic acid only in grape and peach; neochlorogenic acid only in apple and peach; p-coumaric acid only in grape; phloridzin and catechin only in apple. These metabolites in the peels of each fruits were strongly correlated with free radical-scavenging activity and delay of carbohydrate digestion. Therefore, intake of whole fruits, rather than removal of their peels, were recommended for potential improvement of healthy lifespan and human wellness. This study highlights the critical role of metabolomic studies in simultaneous determinations of diverse and intrinsic metabolites in different types of fruits and thus providing a strategy for healthy eating habits of daily fruits.

Optimization of Ultrasound- and Microwave-Assisted Extraction for the Determination of Phenolic Compounds in Peach Byproducts Using Experimental Design and Liquid Chromatography-Tandem Mass Spectrometry

The conversion of plant byproducts, which are phenolic-rich substrates, to valuable co-products by implementing non-conventional extraction techniques is the need of the hour. In the current study, ultrasound- (UAE) and microwave-assisted extraction (MAE) were applied for the recovery of polyphenols from peach byproducts. Two-level screening and Box-Behnken design were adopted to optimize extraction efficiency in terms of total phenolic content (TPC). Methanol:water 4:1% v/v was the extraction solvent. The optimal conditions of UAE were 15 min, 8 s ON-5 s OFF, and 35 mL g^-1, while MAE was maximized at 20 min, 58 °C, and 16 mL g^-1. Regarding the extracts' TPC and antioxidant activity, MAE emerged as the method of choice, whilst their antiradical activity was similar in both techniques. Furthermore, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to determine chlorogenic acid and naringenin in byproducts' extracts. 4-Chloro-4'-hydroxybenzophenone is proposed as a new internal standard in LC-MS/MS analysis in foods and byproducts. Chlorogenic acid was extracted in higher yields when UAE was used, while MAE favored the extraction of the flavonoid compound, naringenin. To conclude, non-conventional extraction could be considered as an efficient and fast alternative for the recovery of bioactive compounds from plant matrices.

Influence of maturity on bruise detection of peach by structured multispectral imaging

Peaches are easily bruising during all stages of postharvest handling, maturity can affect the characteristics and detection of bruising, which is directly related to the quality and shelf life of peach. The main objective of this research was to investigate the effect of maturity on the early detection of postharvest bruising in peach based on structured multispectral imaging (S-MSI) system. The S-MSI data was measured for bruised peaches, followed by microstructural (CLSM), and biochemical (oxidative browning-related enzyme activities, gene expression, and phenolic compound metabolism) measurements. As the maturity increases, the external impact stress could further induce the accumulation of phenolics through the phenylpropane pathway and pulp oxidative browning, resulting in more pronounced external damage; and the spectral reflectance value of bruised peach was getting smaller, and the spectral waveform gradually flattened out. Three characteristic bands of 781, 824, 867 nm were selected from structured spectra (669-955 nm) related to bruising. The watershed algorithm was adopted for bruise detection, the detection rates for bruised peaches based on three maturity levels (S1-S3) were 91-92%, 90.71-97.43%, and 97.14-99.86%, respectively. This research demonstrated that S-MSI system coupled with watershed algorithm, can enhance our capability of detecting the early bruised peaches of different maturity levels.

Leishmanicidal and cytotoxic activity of essential oil from the fruit peel of Myrciaria floribunda (H. West ex Willd.) O. Berg: Molecular docking and molecular dynamics simulations of its major constituent onto Leishmania enzyme targets

Cutaneous Leishmaniasis (CL) is a neglected disease characterized by highest morbidity rates worldwide. The available treatment for CL has several limitations including serious side effects and resistance to the treatment. Herein we aimed to evaluate the activity of essential oil from the peel of Myrciaria floribunda fruits (MfEO) on Leishmania amazonensis. The cytotoxic potential of MfEO on host mammalian cells was evaluated by MTT. The in vitro leishmanicidal effects of MfEO were investigated on the promastigote and intracellular amastigote forms. The ultrastructural changes induced by MfEO were evaluated by Scanning Electron Microscopy (SEM). The molecular docking of the major compounds δ-Cadinene, γ-Cadinene, γ-Muurolene, α-Selinene, α-Muurolene and (E)-Caryophyllene onto the enzymes trypanothione reductase (TreR) and sterol 14-alpha demethylase (C14DM) were performed. Our results showed that MfEO presented moderate cytotoxicity for Vero cells and macrophages. The MfEO inhibited the growth of promastigote and the survival of intracellular amastigotes, in a dose- and time- dependent way. The MfEO presented high selectivity towards amastigote forms, being 44.1 times more toxic for this form than to macrophages. Molecular docking analysis showed that the major compounds of MfEO interact with Leishmania enzymes and that δ-Cadinene (δ-CAD) presented favorable affinity energy values over TreR and C14DM enzymes, when compared with the other major constituents. Molecular dynamics (MD) simulation studies revealed a stable binding of δ-CAD with lowest binding free energy values in MMGBSA assay. Our results suggested that δ-CAD may be a potent inhibitor of TreR and C14DM enzymes. Communicated by Ramaswamy H. Sarma.

Polyhydroxyalkanoate Production from Fruit and Vegetable Waste Processing

Traditional plastics represent a tremendous threat to the environment because of increases in polluting manufacturing as well as their very extended degradation time. Polyhydroxyalkanoates (PHAs) are polymers with similar performance to plastic but are compostable and synthesizable from renewable sources and therefore could be a replacement for fossil-based plastics. However, their production costs are still too high, thus demanding the investigation of new and cheap substrates. In this sense, agricultural wastes are attractive because they are inexpensive and largely available. Specifically, fruit and vegetables are rich in sugars that could be fermented into PHAs. In this work two strains, Cupriavidus necator DSM 545 and Hydrogenophaga pseudoflava DSM 1034, well-known PHA-producing microbes, were screened for their ability to grow and accumulate PHAs. Ten different fruit and vegetable processing waste streams, never before reported in combination with these strains, were tested. Residues from red apple and melon were found to be the most suitable feedstocks for PHA production. Under specific selected conditions, C. necator DSM 545 accumulated up to 7.4 and 4.3 g/L of 3-hydroxybutyrate (3HB) from red apple and melon, respectively. Copolymer production was also obtained from melon. These results confirm the attractiveness of food processing waste as a promising candidate for PHA production. Ultimately, these novel substrates draw attention for future studies on process optimization and upscaling with C. necator.

From Biorefinery to Food Product Design: Peach (Prunus persica) By-Products Deserve Attention

There is an increasing demand for functional foods to attend the consumers preference for products with health benefits. Peach (Prunus persica), from Rosaceae family, is a worldwide well-known fruit, and its processing generates large amounts of by-products, consisting of peel, stone (seed shell + seed), and pomace, which represent about 10% of the annual global production, an equivalent of 2.4 million tons. Some studies have already evaluated the bioactive compounds from peach by-products, although, the few available reviews do not consider peach by-products as valuable materials for product design methodology. Thereby, a novelty of this review is related to the use of these mostly unexplored by-products as alternative sources of valuable components, encouraging the circular bioeconomy approach by designing new food products. Besides, this review presents recent peach production data, compiles briefly the extraction methods for the recovery of lipids, proteins, phenolics, and fiber from peach by-products, and also shows in vivo study reports on anti-inflammatory, anti-obesity, and anti-cerebral ischemia activities associated with peach components and by-product. Therefore, different proposals to recover bioactive fractions from peach by-products are provided, for further studies on food-product design.

Assessment of total concentration and bioaccessible fraction of minerals in peaches from different cultivars by MIP OES

This paper describes studies for the determination of total concentration and bioaccessible fraction of minerals in peaches by MIP OES. The PCA analysis identified 3 distinct groups of elements concerning the total concentration, which was attributed to the origin of each cultivar. Among the macroelements, K presented higher values for total concentration, while B and Fe predominated among the microelements. Regarding the bioaccessible fraction, Mn presented the highest percentage (46-84%), followed by Zn and B (10-63% and 33-57%, respectively). Pearson's correlation coefficient revealed that reducing sugars and titratable acidity can influence the mineral bioaccessibility, highlighting the strong positive correlations between reducing sugars with Mn and total acidity with Fe. Peach cultivars have satisfactory nutritional value, but the total and bioaccessible concentrations of minerals obtained do not meet the recommended daily needs, requiring the consumption of other fruits and vegetables to complement the diet.

Phenotypic diversity of nutritional quality attributes and chilling injury symptoms in four early peach [Prunus persica (L.) Batsch] cultivars grown in west central Tunisia

The present study aimed to characterize the phenotypic diversity of agronomical and biochemical fruit quality traits in four early peach cultivars. The sensibility to chilling injury symptoms (CI) was studied after two cold storage periods (2 and 4 weeks) at 5 ºC and 95% relative humidity (RH) followed by 2 days at room temperature. Agronomical attributes such as fruit weight, firmness, soluble solids content (SSC), pH, titratable acidity (TA) and color parameters were recorded. Antioxidant compounds such as anthocyanins, flavonoids, total phenolics, vitamin C and relative antioxidant capacity (RAC) were evaluated. Chilling injury symptoms such as mealiness, graininess, flesh browning, flesh bleeding, leatheriness and off-flavor were analyzed. Results revealed high antioxidant compounds in peel regarding to flesh fruit. The antioxidant compounds content in both peel and pulp decreased during cold storage except anthocyanins which exhibited different pattern. After 2 weeks of storage, fruits presented high SSC and low score of chilling injury symptoms. At the end of the trial, the studied cultivars were unacceptable for consumption due to the severity of CI. PCA analysis showed that the cultivars Plagold 5 and Plagold 10 had less sensibility to chilling injury.

Graphical abstract

Physicochemical Characteristics, Antioxidant Activities, and Aroma Compound Analysis of Seven Peach Cultivars (Prunus persica L. Batsch) in Shihezi, Xinjiang

Peaches are tasty and juicy, with a unique flavor. The flavors of peaches always vary with cultivars. To investigate the physicochemical and aroma characteristics of peaches, the sugars, organic acids, total flavonoids, phenols, antioxidant activities, and aroma compounds of seven peach cultivars in Xinjiang were determined using high-performance liquid chromatography (HPLC) and headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME–GC–MS). The results showed that sucrose (59.83 to 87.34%), malic acid (32.41 to 59.14%), and chlorogenic acid (10.43 to 45.50%) were the dominant sugar, organic acid, and phenolic compound in peaches, respectively. The antioxidant activity varied between 147.81 and 394.55 μmol TEs/100 g. The analysis of the aroma structure of peaches found that the volatile composition of peaches was relatively consistent, though the concentration of total aroma and certain separate compounds were different between cultivars. Meanwhile, the aroma fingerprint of the peaches consisted of hexyl acetate, cis-3-hexenyl acetate, γ-decalactone, n-hexanal, 2-hexenal, nonanal, decanal benzaldehyde and 6-pentylpyran-2-one, providing a clear green, sweet, floral, and fruity odor. These results provide complete information on the physicochemical properties, functional ingredients and aroma of the peaches.

Evaluation of Two Water Deficit Models on Phenolic Profiles and Antioxidant Activities of Different Peach Fruits Parts

The present work was designed to evaluate the effects of two water shortage strategies on the phenolic profile and antioxidants activities of four Prunus persica L. cultivars (Flordastar, Early May crest, Rubirich and O'Henry). Over the course of two successive seasons (2016 and 2017), three different irrigation strategies were tested: full irrigation (FI: 100 % crop evapotranspiration (Etc)), sustained deficit irrigation (SDI: 50 % ETc), and cyclic deficit irrigation (CDI: irrigation at 100 % field capacity with a soil moisture of 50 % field capacity). HPLC-UV/VIS profile of phenolic compounds, enzymatic and non-enzymatic antioxidant activities were assessed in exocarp and mesocarp. The results showed that deficit irrigation improved the content of phenolic compounds and the antioxidant activities. In O'Henry, ascorbate peroxidase activity increased significantly under CDI in exocarp (249 %). In conclusion, most cultivars showed an improvement of the fruit quality under SDI, whereas O'Henry fruits gathered the highest phenolic amounts and displayed the best antioxidant activity under CDI.

The beneficial effect of peppermint (Mentha X Piperita L.) and lemongrass (Melissa officinalis L.) dosage on total antioxidant and polyphenol content during alcoholic fermentation

Our research aimed to create an herbal fermented alcoholic beverage with high antioxidant and polyphenol content. In this study, continuous sampling was performed throughout the fermentation period, and the changes in total antioxidant (TA) and total polyphenol (TP) contents were determined. After processing the raw material, the prepared herbs were added in 0.5 and 1.0 v/v% concentrations to the samples. The TP content of the control sample was between 1.17 and 1.57 mg/g, and the TA content was 2.12 and 2.54 mg/g during the fermentation process. The lemongrass dosage increased 77.86 % the antioxidant and 70.98 % the polyphenol content by the end of the fermentation process. In the best case, the peppermint dosage increased 72.80 % of the antioxidant content and 72.05 % of the polyphenol content. Overall, fermentation combined with herbs dosage could increase the bioavailability of products made from its polyphenol and antioxidant contents and can be used to develop novel functional foods.

A Comparative and Comprehensive Characterization of Polyphenols of Selected Fruits from the Rosaceae Family

The present research presents a comprehensive characterization of polyphenols from peach, pear, and plum using liquid chromatography coupled with electrospray ionization quadrupole-time-of-flight-mass spectrometry (LC-ESI-QTOF-MS/MS), followed by the determination of their antioxidant potential. Plums showed the highest total phenolic content (TPC; 0.62 mg GAE/g), while peaches showed the highest total flavonoid content (TFC; 0.29 mg QE/g), also corresponding to their high scavenging activities (i.e., DPPH, ABTS, FRAP, and TAC). In all three fruit samples, a total of 51 polyphenolic compounds were tentatively identified and were mainly characterized from hydroxybenzoic acids, hydroxycinnamic acids, hydroxyphenylpentanoic acids, flavanols, flavonols, and isoflavonoids subclasses. Twenty targeted phenolic compounds were quantified using high-performance liquid chromatography with photodiode array detection (HPLC-PDA). The plum cultivar showed the highest content of phenolic acids (chlorogenic acid, 11.86 mg/100 g), whereas peach samples showed the highest concentration of flavonoids (catechin, 7.31 mg/100 g), as compared to pear. Based on these findings, the present research contributes and complements the current characterization data of these fruits presented in the literature, as well as ensures and encourages the utilization of these fruits in different food, feed, and nutraceutical industries.

Valorization of by-products from Prunus genus fruit processing: Opportunities and applications

Food processing, especially the juice industry, is an important sector that generate million tons of residues every. Due to the increasing concern about waste generation and the interest in its valorization, the reutilization of by-products generated from the processing of popular fruits of the Prunus genus (rich in high-added value compounds) has gained the spotlight in the food area. This review aims to provide an overview of the high added-value compounds found in the residues of Prunus fruits (peach, nectarine, donut peach, plum, cherry, and apricot) processing and applications in the food science area. Collective (pomace) and individual (kernels, peels, and leaves) residues from Prunus fruits processing contains polyphenols (especially flavonoids and anthocyanins), lipophilic compounds (such as unsaturated fatty acids, carotenes, tocopherols, sterols, and squalene), proteins (bioactive peptides and essential amino acids) that are wasted. Applications are increasingly expanding from the flour from the kernels to encapsulated bioactive compounds, active films, and ingredients with technological relevance for the quality of bread, cookies, ice cream, clean label meat products and extruded foods. Advances to increasing safety has also been reported against anti-nutritional (amygdalin) and toxic compounds (aflatoxin and pesticides) due to advances in emerging processing technologies and strategic use of resources.

Ultrasound-assisted adsorption/desorption of jujube peel flavonoids using macroporous resins

The work explored the process of ultrasound-assisted adsorption/desorption to efficiently purify jujube peel flavonoids (JPFs) using macroporous resins (MRs). The impact of ultrasound power and temperature on the adsorption/desorption features of JPFs on MRs were studied. The maximum adsorption (80.21 ± 2.11 mg/g) /desorption (76.22 ± 1.68 mg/g) capacity of total flavonoids content were obtained. The pseudo-second-order kinetic and Freundlich isotherm models better described the whole process of ultrasound-assisted adsorption. The adsorption process was spontaneous, physical, and dominated by multilinear intraparticle diffusion. Ultrasound mainly enhanced the adsorption capacity by strengthening the formation of hydrogen bonds and increasing the surface roughness of MRs. Besides, the principal individual flavonoid ((+)-Catechin, (-)-Epicatechin, Rutin, Quercetin-3-O-robinobioside) content of JPFs in ultrasound treatment was 2-3 times that of shaking treatment, and biological activities were significantly increased. Overall, as a low-cost green technology, ultrasound can improve the properties of MRs and better purify JPFs.

Determination of Selected Beneficial Substances in Peach Fruits

Peaches (Prunus persica L.) are a popular and sought-after dessert fruit. This is mainly due to their flavour, aroma, attractive appearance, and high content of substances that play an important role in human nutrition. The present study was carried out to determine some important analytical properties (sugars/sucrose, glucose, fructose and sorbitol), total acid, total phenolics, flavonoids, antioxidant capacity, carotenoids and anthocyanins of 34 selected peach varieties. The analyses are also complemented by colorimetric measurements of peach skin colour using CIELAB and other chromatic parameters. The results show, for example, that all peach varieties are good sources of phenolic compounds (9.43–577 mg gallic acid equivalent (GAE).100 g−1), flavonoids (1.12–95.1 mg catechin equivalent (CAE).100 g−1), and antioxidant capacity (136–462 mg Trolox equivalent (TE).100 g−1).

The changes of physicochemical properties, antioxidants, organic, and key volatile compounds associated with the flavor of peach (Prunus cerasus L. Batsch) vinegar during the fermentation process

Peach is a delicious food preferred by consumers and widely used in the manufacture of peach juice, peach juice concentrate, peach jam, dried fruit, puree, etc. Alternatively, peach can be used in the production of vinegar. In this study, peach vinegar was produced as an alternative to other industrial products produced from peach. In this study, it was determined that the TPC content and ORAC value of peach vinegar were higher than those of peach juice and peach wine. In addition, the major contributor compounds to the aroma profiles of the samples were the γ-decalactone, linalool, and geraniol compounds for the peach juice; the ethanol, ɣ-decalactone, phenylacetic acid, acetic acid, 2-phenylethanol, ethyl decanoate, the linalool, and the decanoic-acid for the peach wine; and the ɣ-decalactone, phenylacetic acid, acetic-acid, phenethyl-acetate, and isovaleric acid for the peach vinegar. It is thought that the results of this study will pave the way for the widespread production of vinegar from peach, which has positive effects on health, is rich in volatile aroma components, and has a high potential to be preferred. Furthermore, this study is the first detailed study so far on peach vinegar. PRACTICAL APPLICATIONS: In this study, it was aimed to produce vinegar as a new and alternative foodstuff product from peach fruit which was normally processed as fresh or/ dried fruit, fruit juice, puree, and canned fruit by the industry. An alternative idea was created for the use of peach fruit, which has a short shelf life. In the study, the antioxidant capacity, organic compounds, and volatile compounds associated with aroma profile of peach vinegar during the fermentation process were determined. Moreover, the changes of these compounds were monitored during the fermentation process. The results of the study are a guide for the usability of peach fruit as a raw material in the production of peach vinegar, which has potentially positive effects on health, is rich in volatile aroma components, and has a high potential to be preferred. Furthermore, this study is the first detailed study on peach vinegar.

Antioxidant Properties of Fruit and Vegetable Whey Beverages and Fruit and Vegetable Mousses

The study assesses the antioxidant activity, total phenolic content, total flavonoids content and lipophilic pigments (β-carotene, chlorophyll a, chlorophyll b) content in homemade and marketed fruit and vegetable whey beverages and fruit and vegetable mousses. All of the tests were performed using spectrophotometric methods. The highest polyphenol content was found in the homemade green whey beverage W1G (541.95 mg/100 g) and the lowest in the market green whey beverage W2G (46.18 mg/100 g). In the fruit and vegetable mousses under study, the highest content of polyphenolic compounds was determined in the red mousse R3 (76.41 mg/100 g). The highest content of flavonoids was observed in the homemade orange whey beverage W1O (63.06 mg/100 g) and in the green mousse G2 (69.80 mg/100 g). The values of the antioxidant activity of whey beverages and mousses varied depending on the composition. The highest content of β-carotene was identified in homemade orange whey beverage (4.36 mg/100 g) and in orange mousses (in range 1.10–2.24 mg/100 g), while chlorophylls a and b—in homemade green whey beverage W1G (3.00 mg/100 g and 1.31 mg/100 g respectively) and in green mousses (chlorophyll a in range 0.54 to 1.42 mg/100 g and chlorophyll b in range 0.13 to 0.32 mg/100 g).

Effect of in vitro digestion on phenolics and antioxidant activity of red and yellow colored pea hulls

To explore the effect of digestion on pea hull phenolics, an in vitro model consisting sequential oral, gastric, small and large intestinal digestions was applied to pea hulls. The phenolic content and antioxidant activity of the samples collected from these digestion steps were determined. The phenolics in these samples generally decreased in the order of sequential digestions in both red and yellow hull series, and no significant increase of total phenolic content (TPC), total flavonoid content (TFC) and individual phenolics were found in most digested groups compared with the corresponding control groups. The antioxidant activity of the samples generally changed according to their TPC and strong correlations (r > 0.92, p < 0.001) existed between them in red hull series. The present study implies that phenolics are released gradually from pea hulls during in vitro digestion and their release was mainly due to the pH of the digestion.

Development and application of a liquid chromatography-mass spectrometry method for the determination of sugars and organics acids in araza, ceriguela, guava, mango and pitanga

Abstract The intrinsic characteristics of many tropical fruits cause high post-harvest losses and prevent their commercialization as fresh fruits. Information about their composition is crucial for defining processing conditions and identifying opportunities for product development. However, the analytical methods generally used to quantify sugars and organic acids are costly and time-consuming. Simultaneous analysis by Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (LC-ESI-MS/MS) is a very sensitive and reproducible technique, allowing for accurate simultaneous multi-analyte quantitation in complex systems. Thus, a LC-ESI-MS/MS Multiple Reaction Monitoring (MRM) method was developed using reverse phase column for detecting and quantifying sugars and some organic acids in only 4 min, in selected fruits as following: araza (Psidium cattleianum L.), ciriguela (Spondias purpurea L.), mango (Mangifera indicaL.), guava (Psidium guajava L.) and pitanga (Eugenia uniflora L.). All fruits had a similar concentration of glucose and fructose, except for pitanga that presented higher values of both. The content of citric, malic and tartaric acids was quantitated; some fruits stood out by their high content of organic acids, for instance, araza was rich in citric acid. The newly generated data on the composition of tropical fruits allowed establishing a correlation between the carbohydrate content and the physical properties of the fruit pulps, assist in product development.

Early metabolic priming under differing carbon sufficiency conditions influences peach fruit quality development

Crop load management is an important preharvest factor to balance yield, quality, and maturation in peach. However, few studies have addressed how preharvest factors impact metabolism on fruit of equal maturity. An experiment was conducted to understand how carbon competition impacts fruit internal quality and metabolism in 'Cresthaven' peach trees by imposing distinct thinning severities. Fruit quality was evaluated at three developmental stages (S2, S3, S4), while controlling for equal maturity using non-destructive visual to near-infrared spectroscopy. Non-targeted metabolite profiling was used to characterize fruit at each developmental stage from trees that were unthinned (carbon starvation) or thinned (carbon sufficiency). Carbon sufficiency resulted in significantly higher fruit dry matter content and soluble solids concentration at harvest when compared to the carbon starved, underscoring the true impact of carbon manipulation on fruit quality. Significant differences in the fruit metabolome between treatments were observed at S2 when phenotypes were similar, while less differences were observed at S4 when the carbon sufficient fruit exhibited a superior phenotype. This suggests a potential metabolic priming effect on fruit quality when carbon is sufficiently supplied during early fruit growth and development. In particular, elevated levels of catechin may suggest a link between secondary/primary metabolism and fruit quality development.

Determination of Biochemical Composition in Peach (Prunus persica L. Batsch) Accessions Characterized by Different Flesh Color and Textural Typologies

The rising interest in beneficial health properties of polyphenol compounds in fruit initiated this investigation about biochemical composition in peach mesocarp/exocarp. Biochemical evaluation of phenolic compounds and ascorbic acid were quantified through high-performance liquid chromatography (HPLC) in relation to three flesh colors (white, yellow and red) and four flesh typologies (melting, non-melting, slow softening and stony hard) within six commercial cultivars and eight breeding selections of peach/nectarine in 2007. While in 2008, quality and sensorial analyses were conducted on only three commercial cultivars (‘Big Top’, ‘Springcrest’ and ‘Ghiaccio 1’). The red flesh selection demonstrated the highest levels of phenolic compounds (in mesocarp/exocarp) and ascorbic acid. Total phenolic concentration was approximately three-fold higher in the exocarp than the mesocarp across all accessions. Breeding selections generally reported higher levels of phenolics than commercial cultivars. Flesh textural typologies justified firmness differences at harvest, but minimally addressed variations in quality and phenolic compounds. Flesh pigmentation explained variation in the biochemical composition, with the red flesh accession characterized by an abundancy of phenolic compounds and a high potential for elevated antioxidant activity. Sensorial analyses ranked the cultivar with high soluble solids concentration:titratable acidity (SSC:TA) and reduced firmness the highest overall. Red flesh is a highly desirable trait for breeding programs aiming to improve consumption of peaches selected for nutraceutical properties.

Profiles of Sugar and Organic Acid of Fruit Juices: A Comparative Study and Implication for Authentication

A comparison of sugar and organic acid profiles among different fruit juices (including apple, pear, peach, grape, sweet cherry, strawberry, and blueberry with various varieties) was performed to assess the possibility for authentication coupled with chemometrics. It was found that the distribution of each sugar and organic acid in juices showed some specific characteristics related to fruit species, despite the fact that great differences in the content existed among different varieties. Sucrose was the most abundant sugar in peach juice, accounting for 58.26–77.11% of the total sugar content. However, in grape, blueberry, and sweet cherry juice, glucose and fructose were the predominant sugars. Pear juice contained the highest level of sorbitol, which contributed to 15.02–43.07% of the total sugar content. Tartaric acid was detected only in grape juice among the seven species of fruit juice, with a proportion of 57.95–89.68% in the total acid content. Malic acid was the predominant organic acid in apple and sweet cherry juice, accounting for 69.92–88.30% and 97.51–98.73% of the total acid content of each species. Citric acid was the predominant organic acid in strawberry and blueberry juice, which contributed to 62.39–83.73% and 73.36–89.56% of the total acid content of each species. With the aid of principal component analysis and linear discriminant analysis (LDA), the juice samples could be successfully classified according to fruit species by using the sugar and/or organic acid composition as analytical data. Combination of sugar and organic acid composition gave the best differentiation of these seven species of juices, with a 100% correct classification rate for both the original and the cross-validation method in LDA. Adding malic/citric into the dataset of the organic acid content may also improve the differentiation effect. Furthermore, the adulteration of sweet cherry juice, blueberry juice, raspberry juice, and grape juice with apple juice, pear juice, or peach juice could also be distinguished from their corresponding pure juices based on sugar and organic acid composition by LDA.

The outer influences the inner: Postharvest UV-B irradiation modulates peach flesh metabolome although shielded by the skin

UV-B-driven modulation of secondary metabolism in peach fruit by enhancing the biosynthesis of specific phenolic subclasses, is attracting interest among consumers. However, current literature explored the UV-B-induced metabolic changes only in peach skin subjected to direct UV-B irradiation. Accordingly, this study aimed to understand whether UV-B radiation penetrates the fruit skin and is able to induce metabolic changes also within the inner flesh. Peaches were UV-B-irradiated either 10 or 60 min, and the flesh was sampled after 24 and 36 h. Non-targeted metabolomics revealed that UV-B has a strong impact on peach flesh metabolome, determining an initial decrease after 24 h, followed by an overall increase after 36 h, particularly for terpenoids, phenylpropanoids, phytoalexins and fatty acids in the 60 min UV-B-treated samples (+150.02, +99.14, +43.79 and +25.44 log₂FC, respectively). Transmittance analysis indicated that UV-B radiation does not penetrate below the skin, suggesting a possible signalling pathway between tissues.

Nutritional composition of conserved Kadsura spp. plants in Northern Thailand

The genus Kadsura comprises woody vine plants belonging to the family Schisandraceae. Species are found mostly in Northern Thailand and widely consumed by the local population. Occurrences of these wild fruits are rare as they only grow naturally in forest areas. Nutritive values of Kadsura spp. remain unclear, leading to improper management for food applications. Nutritional composition of Kadsura spp. was evaluated to promote sustainable conservation. Nutritive values in different fruits parts (exocarp, mesocarp, seed and core) of two Kadsura species as Kadsura coccinea (Lem.) A.C. Sm. and Kadsura heteroclita (Roxb.) Craib, from Chiang Rai Province, Thailand were assessed. When comparing nutritional contents based on per 100 g dry weight, results suggested that K. coccinea exhibited higher carbohydrate (1–2 times), sugar (1–2 times) and vitamin C (3–4 times) contents than K. heteroclita, while the latter possessed higher fat (1–2 times), protein (1.6–1.9 times), and dietary fiber (1.5–1.8 times) contents. Considering each fruit part, the mesocarp (the only edible fruit part) and exocarp of both species provided high dietary fiber (11.6–20.9% recommended dietary fiber) and vitamin C (as high as 73% recommended per day) but were low in energy (30–40 kcal/100 g fresh weight), protein (0.6–1.2% recommended per day), fat (0.5–1.8% recommended per day) and sugar (2.4–5.4% recommended per day). Interestingly, seed contained higher energy (1–2 times), protein (2–3 times) and fat (4–50 times) than the other fruit parts. Results support the potential consumption of Kadsura spp. as a healthy fruit that can be used for future food applications. Seed and exocarp from Kadsura spp. also showed potential for new product development.

Is the Tolerance of Commercial Peach Cultivars to Brown Rot Caused by Monilinia laxa Modulated by its Antioxidant Content?

Brown rot, caused by Monilinia spp., provokes pre- and post-harvest damage in peach (Prunus persica (L.) Batsch), which causes an economic impact in the industry. With a view to breeding for increased tolerance to this disease, a screening test based upon artificial fruit inoculation was validated on several parental lines of a peach breeding program during the two-period harvest. In addition, cultivars with different total phenolic contents were included in the two-year study. All physicochemical fruit traits recorded at harvest showed differences among all cultivars. The antioxidant compound content determined using spectrophotometry (to measure ascorbic acid and antioxidant capacity) and UPLC-MS (to measure and identify phenolic compounds) also revealed important differences among all genotypes. The rate of brown rot lesion following fruit inoculation varied widely among cultivars, and it was possible to discriminate between highly and less susceptible cultivars. Cultivars with minimal development of damage were identified as germplasm with the desirable allele combination to increase brown rot tolerance in peach breeding programs. Finally, Pearson’s correlation coefficients (r) between pairs of variables were calculated, searching for any biochemical candidate conferring tolerance. The correlation of phytopathological traits with the antioxidant composition, concerning contents of ascorbic, neochlorogenic, and chlorogenic acids and total polyphenols in fruit, is discussed.

Effect of high levels of CO2 on the electrochemical behavior and the enzymatic and non-enzymatic antioxidant systems in black and white table grapes stored at 0 °C

BACKGROUND

In this study, we analyzed the effect of the application of high levels of CO₂ (20 kPa CO₂  + 20 kPa O₂  + 60 kPa N₂ ) for 3 days at low temperature on a white table-grape cultivar (Superior Seedless) in comparison with a black one (cv. Autumn Royal) in terms of quality parameters. We also used a solid-state voltammetry methodology to analyze the effect of the 3-day gaseous treatment in berry tissues from both cultivars in the first stage of storage. We determined the role of the non-enzymatic (total phenols, total anthocyanins, and antioxidant activity) and the enzymatic antioxidant (catalase (GCAT), ascorbate peroxidase (VcAPX) gene expression) systems in the behaviors of both cultivars.

RESULTS

Our results indicate that the application of a 3-day gaseous treatment was effective in maintaining the quality of black and white table grapes for up to 28 days of storage at 0 °C. The electrochemical methodology applied was useful for differentiating between skin and pulp samples, and between black and white table grape cultivars. Some molecular mechanisms were modulated in the skin of both cultivars to overcome oxidative stress, which was not manifested with the same intensity in grapes treated with CO₂ for 3 days. However, some differences were observed in relation to the non-enzymatic system.

CONCLUSION

The 3-day gaseous treatment was useful to maintain black and white table grape quality at 0 °C. The voltammetry analysis indicated that CO₂ -treated samples from the skin and pulp showed more similarity to freshly harvested ones. © 2019 Society of Chemical Industry.

Cytotoxic, antimicrobial and nitric oxide inhibitory activities of supercritical carbon dioxide extracted Prunus persica leaves

Different parts of Prunus persica as fruits, flowers, leaves and kernels have been consumed with dietary and therapeutic purposes traditionally. During fruit production, remarkable amount of leaves which can hold important bioactive groups as phenolics, have been left unutilized. The aim of this study was to investigate cytotoxic, antimicrobial and nitric oxide inhibitory activities of supercritical carbondioxide extracts of Prunus persica leaves. Among studied cell lines, supercritical carbon dioxide extract which was processed at 150 bar, 60 °C, and 6% co-solvent ethanol, exhibited remarkable cytotoxic activity against HeLa, MPanc-96 and MCF-7 cell lines with IC₅₀ values of 12.22 µg/ml, 28.17 µg/ml and 35.51 µg/ml respectively, whereas IC₅₀ value of conventional solvent extract was above 50 µg/ml. Minimum inhibitory concentration values determined for antibacterial and antifungal activities against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Enterococcus faecium and Candida albicans were found as 62.50 µg/ml. Strong nitric oxide inhibition was achieved with IC₅₀ of 9.30 µg/ml. The promising results revealed that Prunus persica leaves may have remarkable potential as supplement both for drug and food industries. This study is the first report revealing cytotoxic, antimicrobial and nitric oxide inhibitory activity of supercritical carbon dioxide extract of Prunus persica leaves.

Relationship between fruit density and quality parameters, levels of sugars, organic acids, bioactive compounds and volatiles of two nectarine cultivars, at harvest and after ripening

In this study, fruits of two nectarine cultivars, harvested at commercial ripeness, were sorted into three density groups. Physicochemical parameters (mean weight, firmness, dry matter, soluble solids content, titratable acidity) and the levels of sugars, organic acids, vitamin C, polyphenols and volatiles were then determined at harvest and after ripening. A sensory ranking test was also performed on ripened nectarines to compare quality attributes (firmness, sweetness, acidity, and aroma). In both cultivars, ripened nectarines of higher density had significantly higher levels of dry matter, soluble solids content, sugars, ascorbic acid, polyphenols and volatiles. Among polyphenols, the levels of hydroxycinnamic acids were 30-40% significantly higher in nectarines of higher density. Among volatiles, levels of lactones, well-known key aroma compounds in nectarines, were also 2-3 times significantly higher in ripened fruits of higher density. Consistent with these results, nectarines of higher density were significantly ranked sweeter and more aromatic in both cultivars.

Citric acid treatment reduces decay and maintains the postharvest quality of peach (Prunus persica L.) fruit

Peaches are easily perishable fruit, and their quality is quickly lost after harvest. In this study, "Hujingmilu" peach (Prunus persica L.) fruit was treated with citric acid (CA) and stored at 20°C for 15 days. Fruit decay and quality were evaluated during the storage period. Compared with the control, CA treatment did not inhibit climacteric ethylene release, but CA was significantly effective at maintaining firmness, inhibiting decay, and preventing a decrease in titration acid (TA). CA treatment inhibited the increase in total soluble solids (TSS), sucrose, and fructose in the first week after fruit harvest, but then their content was significantly higher in CA-treated fruits than that in the control group. The decrease in malic acid and citric acid was significantly prevented by CA treatment. During storage, the concentrations of C6 volatile compounds decreased rapidly whereas lactones sharply increased, and the concentrations of δ-decalactone, γ-decalactone, and γ-dodecalactone were found to be significantly high in CA fruits compared with the control after the eighth day of storage (p < .05). Similarly, higher contents of chlorogenic acid, neochlorogenic acid, catechin, and L-epicatechin were maintained in fruits treated with CA during the same storage period (p < .05). Our findings suggest that treatment with 10 g/L citric acid can reduce postharvest decay and effectively maintain the texture, flavor, and nutrition quality of peach fruit.

Phenolic composition and antioxidant activities of saskatoon berry fruit and pomace

Total phenolic chromatographic indices (TPCI) of three commercially grown saskatoon berry varieties and a pomace from commercial juice production were determined. Northline was shown to have the highest TPCI of 504.2 mg/100 g FW. These results agreed with total phenolic content results for these varieties. The TPCI of the commercial pomace was 404.2 mg/100 g pomace indicating that a significant concentration of phenolics were present in this co-product, showing the commercial relevance of this material. A phenolic rich extract (PRE; 500 ppm) of the Northline variety was compared to BHT (0.02% w:w) and Rosamox (0.2% w:w) for delaying the oxidation of borage oil via rancimat analysis. Induction times were 1.46 h (borage oil), 1.44 h (Rosamox), 2.18 h (BHT), and 2.42 h (PRE), which was a ∼65% delay in the oxidation of borage oil. These results clearly support the value of this material as an antioxidant ingredient in foods, pharmaceuticals, nutriceuticals and cosmetics.