Francisca Hernández

Volatile Composition of Pomegranates from 9 Spanish Cultivars Using Headspace Solid Phase Microextraction

Fruits of 9 Spanish pomegranate cultivars were analyzed for quality parameters, volatile composition, and sensory profile. Volatile compounds were extracted using headspace solid phase micro-extraction (HS-SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS) and flame ionization detector (GC-FID). Twenty-one compounds were found in the headspace of fresh pomegranate juices, including aldehydes, monoterpenes, and alcohols. The most abundant compounds were hexanal, limonene, trans-2-hexenal, and cis-3-hexenol. Fruits from the cultivars Mollar Elche(ME) ME14, ME1, and ME2 presented the highest values of overall liking by the consumer panel; however, their total volatiles concentration were low compared to the other pomegranate cultivars and their color intensity was intermediate. Overall consumer liking of pomegranate juices was mainly associated with the presence of monoterpenes (α-terpineol); however, high aldehydes (trans-2-hexenal) concentrations were correlated with poor overall consumer liking. Fruits from sour-sweet cultivars (PTO7 and ADO4) could improve the quality of ME pomegranate juices due to their intense color, high monoterpenes concentrations, and their moderate sourness. Practical Application: The information provided in this study proves that sour-sweet pomegranate fruits can be used in the manufacturing of pomegranate juices and will improve the sensory quality and the volatile composition of this product.

Potential of Spanish sour–sweet pomegranates (cultivar C25) for the juice industry

Commercial juices of sweet pomegranates and fresh juices of sour–sweet pomegranates were analysed for organic acids, sugars, antioxidant activity, volatile composition, sensory profile and consumer liking. Organic acids and sugars were analysed by high-performance liquid chromatography, while volatiles were extracted using hydrodistillation and analysed by gas chromatography–mass spectrometry and gas chromatography–flame ionisation detector. Malic acid was predominant in sweet juices while citric acid in sour–sweet samples. Fructose and glucose were found as the predominant sugars in all juices. A total of 18 compounds were found in pomegranate aroma profile, including monoterpenes, aldehydes, alcohols, monoterpenoids and linear hydrocarbons; the most abundant compounds were 3-carene, α-terpinene and α-terpineol. The total concentration of volatiles ranged from 2.0 up to 5.1 mg/L, with commercial samples presenting higher total concentrations due to the presence of peel volatiles. The high potential of sour-sweet pomegranate fruits for the juice industry was supported by (a) the high values of positive attributes, such as colour and fresh pomegranate flavour and (b) the high overall liking of consumers.

Organic Acids, Sugars, and Anthocyanins Contents in Juices of Tunisian Pomegranate Fruits

Juices made from fruits of 30 Tunisian accessions of pomegranate were studied for their organic acids, sugars, and anthocyanin contents, using high performance liquid chromatography. Among the detected organic acids, malic acid was the major one (>50%) followed by citric acid (>22%), while among sugars, fructose and glucose were most present in pomegranate juice contributing 53.9 and 43.4% of the total sugar content, respectively. The total anthocyanin content ranged from 9–115 mg per litre of juice with the following ranges of the six compounds found: cyanidin-3,5-diglucoside (3.1–74.4 mg/L), delphinidin-3-glucoside (0.7–22.0 mg/L), cyanidin-3-glucoside (0.8–21.0 mg/L), pelargonidin-3-glucoside (0.5–16.1 mg/L), pelargonidin-3,5-diglucoside (0.0–11.8 mg/L), and delphinidin-3,5-diglucoside (0.0–5.4 mg/L). Based on the analyzed parameters, cluster analysis allowed grouping cultivars into two main clusters. One was made of sour cultivars and the second of the sweet ones. Principle component and cluster analyses suggested that the composition of the pomegranate fruits is determined by cultivar rather than cultivation location.

Physico-chemical, nutritional, and volatile composition and sensory profile of Spanish jujube (Ziziphus jujuba Mill.) fruits.

BACKGROUND Jujube fruit is eaten mostly fresh, but may be dried (Chinese dates and tea) or processed into confectionary recipes in bread, cakes, compotes, and candy. Given that the quality of jujube available on the market differs on account of various factors such as geographical environment, cultivar, processing conditions, and storage conditions, and that, for consumers, flavour and nutrition properties of jujube represent the major parameters in determining the quality of jujube, the main goal of this study were to determine the main physico-chemical properties of jujube fruits, sugars and organic acids profiles, protein, mineral constituents, volatile composition and sensory profile of jujube fruits. This would allow breeders to select cultivars with higher levels of nutrients and also enable increasing dietary intake by consumers. RESULTS Investigations showed that jujube fruit weight ranged from 4.8 to 29.3 g fruit(-1) . Four sugars (glucose, fructose, sucrose and sorbitol) and four organic acids (citric, malic, ascorbic and succinic acids) were identified and quantified by high-performance liquid chromatography in jujube fruits. Potassium, calcium and magnesium were the major mineral constituents in jujube fruits. Fifteen volatiles compounds were found in the aroma profile of jujube fruits (nine were aldehydes, three terpenes, one ester, one ketone and one linear hydrocarbon). CONCLUSION The results showed that Spanish jujube cultivars studied are a good source of vitamin C, and they have a low content of Na. The jujube cultivar with the most appreciated quality by consumers was GAL; the GAL fruits were sweet, crunchy, and had high intensities of jujube ID and apple flavour a long after-taste. Therefore, jujube grown in Spain has a great potential to be exploited for functional foods.

Phytochemical and quality attributes of pomegranate fruits for juice consumption as affected by ripening stage and deficit irrigation.

BACKGROUND Pomegranate (PG) is a drought resistant crop, thriving well with scarce water resources. The non-climateric character of PG remarks the importance of determining the optimum harvest time to improve quality and phytochemical properties of PG. RESULTS The influence of two different irrigation treatments on physico-chemical and phytochemical parameters of PG was assessed. Control trees (T0) were over irrigated (105% ETo). From the beginning of the second half of rapid fruit growth period to the last harvest, T1 plants were subjected to sustained deficit irrigation (33% ETo). Results indicated that T1 fruits exhibited a darker and more intense garnet colour than T0 fruits, but deficit irrigation led to a significant decrease in total fruit yield and number of total fruits per tree. T1 fruits showed similar bioactive quality than T0 fruits; however, T1 fruits advanced the optimal harvest time by about 7-8 days with respect to T0 fruits. CONCLUSIONS Late-pomegranate fruits were rich in phytochemicals and could be of great interest to the juice industry. Knowledge of these trends is important, especially to improve PG juice quality and to contribute to the sustainability of PG culture with respect to water, fertiliser and energy saving.

(Poly)phenolic fingerprint and chemometric analysis of white (Morus alba L.) and black (Morus nigra L.) mulberry leaves by using a non-targeted UHPLC-MS approach.

This study reports the (poly)phenolic fingerprinting and chemometric discrimination of leaves of eight mulberry clones from Morus alba and Morus nigra cultivated in Spain. UHPLC-MS(n) (Ultra High Performance Liquid Chromatography-Mass Spectrometry) high-throughput analysis allowed the tentative identification of a total of 31 compounds. The phenolic profile of mulberry leaf was characterized by the presence of a high number of flavonol derivatives, mainly glycosylated forms of quercetin and kaempferol. Caffeoylquinic acids, simple phenolic acids, and some organic acids were also detected. Seven compounds were identified for the first time in mulberry leaves. The chemometric analysis (cluster analysis and principal component analysis) of the chromatographic data allowed the characterization of the different mulberry clones and served to explain the great intraspecific variability in mulberry secondary metabolism. This screening of the complete phenolic profile of mulberry leaves can assist the increasing interest for purposes related to quality control, germplasm screening, and bioactivity evaluation.

Evaluation of Spanish Pomegranate Juices: Organic Acids, Sugars, and Anthocyanins

Six pomegranate (Punica granatum L.) cultivars belonging to the ‘Mollar’ group were evaluated under homogeneus growing conditions. Chemical parameters, such as sugars, organic acids, and anthocyanin contents, and other quality parameters, including fruit weight, pH, total soluble solids, titratable acidity, and colour, were evaluated. Fruit weight was not significantly affected by cultivar. The highest TSS content was detected in juice from MO6 (15.81 °Brix). All cultivars were sweet, and the ripening index ranged from 59.14 (ME5) to 87.95 (MO6). The composition of pomegranate juice was dependent on the cultivar. Glucose was the major sugar in all evaluated cultivars (60–64% of total sugars), followed by fructose, maltose, and sucrose. Among the detected organic acids, citric acid was the predominant (>54%). The total anthocyanin content ranged from 72 to 200 mg per litre of juice, being the main anthocyanin cyanidin 3-glucoside followed by cyanidin 3,5-diglucoside. The principal component analysis and cluster analysis showed high dissimilarity levels in cultivars ME5, MO6, MA4, and MA5.

Fatty acids composition of Spanish black (Morus nigra L.) and white (Morus alba L.) mulberries

This research has determined qualitatively and quantitatively the fatty acids composition of white (Morus alba) and black (Morus nigra) fruits grown in Spain, in 2013 and 2014. Four clones of each species were studied. Fourteen fatty acids were identified and quantified in mulberry fruits. The most abundant fatty acids were linoleic (C18:2), palmitic (C16:0), oleic (C18:1), and stearic (C18:0) acids in both species. The main fatty acid in all clones was linoleic (C18:2), that ranged from 69.66% (MN2) to 78.02% (MA1) of the total fatty acid content; consequently Spanish mulberry fruits were found to be rich in linoleic acid, which is an essential fatty acid. The fatty acid composition of mulberries highlights the nutritional and health benefits of their consumption.

Effects of brassinosteroid analogues on total phenols, antioxidant activity, sugars, organic acids and yield of field grown endive (Cichorium endivia L.).

BACKGROUND Cichorium endivia L., either cooked or eaten raw in salads, is a favourite cultivated vegetable around the world and the popularity is attributed to its healthy properties, which are mainly due to its high levels of antioxidant compounds and high content of minerals, provitamin A and vitamins. Brassinosteroids are a family of hormones that are found in plants and which serve as potent growth promoters. The effects of two brassinosteroid analogues, DI-31 and DI-100, were evaluated at concentrations of 4, 8 and 12 ppm together with a seaweed extract and amino acid mixture called Tomex Amin to enhance their activity. RESULTS All treatments with DI-100 and DI-31 resulted in the highest production increases. The chemical variables related to endive quality, such as moisture, carbon and nitrogen content, sugar and organic acid content were similar in the control and treated endives. Total antioxidant activity and total phenols increased significantly in endive treated with brassinosteroid analogues. CONCLUSION The results showed that sprayed brassinosteroid analogues mixed with Tomex Amin may play an important role in increasing the yield and the contents of total antioxidant activity and total phenols of field grown endives.

Pomegranate juice adulteration by addition of grape or peach juices.

BACKGROUND Pomegranate juice has gained a high reputation for its health properties and consequently is now a highly demanded product. However, owing to the limited production and high price of fresh pomegranates, adulteration of pomegranate juice seems to be happening. Hence it is imperative to establish criteria for detecting adulteration. RESULTS Addition of grape juice significantly increased the contents of Ca, Mg and Fe and especially tartaric acid and proline and simultaneously decreased the content of K. Addition of peach juice up to 10% (v/v) only resulted in a significant increase in sucrose content. Regarding the volatile composition, adulteration of pomegranate juice with grape juice resulted in significant increases in acetic acid, isoamyl butyrate and especially 1-hexanol and linalool, while adulteration with peach juice resulted in significant increases in butyl acetate, isobutyl butyrate, benzyl acetate and especially isoamyl butyrate. CONCLUSION The control protocols used in this study can serve as a basis for identification of pomegranate juice adulteration. It is important to highlight that it is necessary to simultaneously analyze and have results from several parameters to conclude that a particular pomegranate juice has been adulterated by mixing with another fruit juice.