Ángel Calín-Sánchez

Volatile composition and sensory quality of Spanish pomegranates (Punica granatum L.)

BACKGROUND Pomegranate is highly valued for its health-promoting effects. Fruits of nine pomegranate cultivars were analysed for volatile compounds, antioxidant activity and quality parameters, including maturity index and CIEL*a*b* colour. Volatile compounds were isolated from fresh juices using hydrodistillation; extracts were analysed using gas chromatography/mass spectrometry. Fruit colour was influenced by cultivar and grouping of cultivars according to their taste (sweet, sour-sweet or sour), with sweet fruits having more intense red colour and higher lightness values. RESULTS A total of 18 compounds were found in pomegranate aroma profiles, including monoterpenes, aldehydes, alcohols, monoterpenoids and linear hydrocarbons. The most abundant compound were trans-2-hexenal, 3-carene, α-terpinene and α-terpineol. The total concentration of volatiles ranged from 1.7 to 10.9 g kg(-1) . Overall consumer liking of pomegranate juices was associated with the presence of monoterpenes such as α-pinene, β-pinene, β-myrcene, limonene and γ-terpinene. The presence of aldehydes such as hexanol, hexanal and cis-3-hexenol was correlated with poor overall consumer liking. CONCLUSION Fruits from the cultivar Mollar de Elche 2 were those most suited for juice processing because they had the highest total concentration of volatiles, which was related to high overall consumer liking, intense and acceptable fresh pomegranate odour and flavour (high scores of satisfaction degree), medium intensity of red colour and low sourness.

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.

Effects of Drying Methods on the Composition of Thyme (Thymus vulgaris L.) Essential Oil

The influence of drying method on aroma compounds of thyme (Thymus vulgaris L.) was evaluated. The drying methods tested were convective drying, vacuum–microwave drying, and freeze drying, as well as a combination of convective predrying and VM finish drying. Thymes convective drying kinetics are described by a two-term exponential model, and VM drying kinetics consisted of two periods: a constant rate period until a critical moisture ratio (values of 0.311, 0.242, and 0.162 kg kg−1 for 240, 360, and 480 W, respectively) was obtained and a falling rate period beyond that point. Volatile compounds of thyme samples were extracted by hydrodistillation and analyzed by gas chromatography. Thirty-three compounds were tentatively identified; thymol, γ-terpinene, p-cymene, caryophyllene, and α-terpinene were the major components. The total quantity of volatiles of fresh thyme (1,167 mg 100 g−1 db) was reduced by most of the drying treatments, with the exception of VM at 240 and 360 W. The combined method with 40°C and 240 W was the best option for drying thyme; the time required was relatively short (≈ 301 min) and aroma quality was good according to instrumental data (total concentration of volatiles 1,127 mg 100 g−1 db) and sensory evaluation results (high scores for fresh thyme and vegetable odors).

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.

Effects of Cyclodextrin Type on Vitamin C, Antioxidant Activity, and Sensory Attributes of a Mandarin Juice Enriched with Pomegranate and Goji Berries

UNLABELLED The effects of the addition of cyclodextrins (CDs), β-CD, or HP-β-CD (1%), on the protection of antioxidant compounds of mandarin juices enriched with pomegranate extract and goji berries juice, was studied. Juices were prepared and after their thermal treatment (98 °C, 30 s) they were stored at 4 °C during 75 d. Vitamin C content, CIE L*a*b* color, antioxidant capacity, retinol equivalents, and sensory properties were studied. Losses on vitamin C were higher (6%) for juices with β-CD than juices with HP-β-CD. Retinol equivalents degradation was lower (3.4%) in juices with HP-β-cyclodextrins than in those treated with β-CD. Lower losses were observed for the instrumental and sensory color intensity in juices with HP-β-CD addition. Finally, the antioxidant capacity was also higher in juices treated with HP-β-CD. Finally, the overall sensory quality of juices with HP-β-CD was the best one after 30 d of cold storage. Even though β-CD addition did not cause any improvement compared with control juice (without CD addition), the benefits of adding HP-β-CD to this particular juice were shown in almost all parameters under study. PRACTICAL APPLICATION  The present study deals with the practical aspects of the utilization of CDs and CD-complexes in the food industry. The molecular encapsulation of lipophilic food ingredients with CD are supposed to improve the stability of flavors, vitamins, colorants, and antioxidant activity, leading to extended product shelf life. The HP-β-CD treated mandarin juice enriched with pomegranate extract and juice of goji berries will have a more intense color, higher vitamin C content, retinol equivalents, and antioxidant activity during storage and shelf life than control juices, with no CD addition.

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.