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Analytical and sensory evaluation of two strawberries cultivars to improve market acceptability
No full textTwo strawberry cultivars (Fragaria × ananassa Duch.), ‘Miss’ and selection ‘94.568.2’ (‘Queen Elisa’), grown in two areas of North Italy, were investigated in 2002 and 2003. Objective physicochemical qualities of fruit, their storability and their sen-sory qualities were used to demonstrate the differences between the two cultivars and to improve their market acceptability. Since previous sensory evaluation in strawber-ries has shown that consumer preference is influenced mainly by sensory attributes including aroma, a second aim of this investigation was to characterize the volatile composition of the fruits of these two cultivars using GC-MS, GC-FID and GC-olfactometry (GCO) techniques. Objective and sensory results showed that ‘Queen Elisa’ had better characteristics (sweetness, acidity and firmness). Total content of aroma compounds analysed by GC-FID was higher for ‘Miss’. The GCO assays indi-cated that ‘Queen Elisa’ had a better odour profile than ‘Miss’. The latter cultivar showed a high sensory perceptibility of methyl butanoate, and of a compound not identified, associated with unpleasant odours (seasoned cheese and sulphurated smell)
Caratterizzazione aromatica di due genotipi di fragole mediante analisi GC-MS e HS-SPME-GC
No full textREALIZZAZIONE DI UN NUOVO INGREDIENTE ALIMENTARE A BASE DI PETALI DI ROSA: ASPETTI NUTRACEUTICI E TECNOLOGICI
No full textThe aim of this PHD project was to study the suitability of flowers as nutraceutical, technological and healthy sources, in order to produce a new food ingredient.
A case study for the research, the Rosa botanical species was chosen, because the petals are rich in nutritional compounds and are normally used in gastronomical and phytotherapic field. However the scientific information about their chemical-nutritional and technological properties are, at the moment, fragmentary, in particular because the use of roses as food ingredients are very unconventional. For this reason we prefer to pinpoint the innovative characteristics of this study. A particular aspect of the study was related to the ways to produce and obtain raw material. The roses were cultivated in a protected, natural and chemical, phytochemical free environment. The organic cultivation of flowers for nutritional use, could encourage a new kind of vegetable production in a sector where, normally, the use of pesticides is absolutely necessary.
The first scientific step of the study was the chemical characterization of the organically grown roses varieties both as raw material and during processing, in order to obtain an ingredient suitable for several destinations. In this case, there is also a lack of scientific literature regarding chemical and biochemical properties of ingredients, or final products, obtained directly from floricultural matrix (not from flower extracts or by-products).
One of the targets of this research was to realize a formulation of an ingredient, rose petal based, for basic food like yogurt, that is in itself considered a functional food.
The floricultural matrix could offer interesting opportunities not only for garden nurseries or organic flower producers, but also in order to diversify the yogurt production. In this case, in fact, the dairy makers could combine the benefits of the bio-active compound of the flowers with the well known beneficial contribution of the yogurt. The relationship between technological processing of the petals, their phase composition and chemical, microbiological, functional characteristics of the new ingredient, were studied. In particular, for raw material quality evaluation, specific analytical protocols were established, in order to determine chemical-nutritional and nutraceutical parameters,
Nutraceutical composition of the flowers was focused both in terms of specific molecules or antioxidant compound groups such as: ascorbic acid, polyphenols, total anthocyanins and also in terms of antiradicalic activity, expressed as scavenger effect. DPPH and Fremy’ salt, methods, were the most representative analytical ways used for these determinations.
The correct composition of vegetable ingredient (rose petals), in the model mixture under study, was accurately calculate and tested in various attempts. Then this innovative formulation was stabilized microbiologically by applying a specific and targeted thermal treatment. The same analysis carried out on raw material (extraction and characterization of the bio-active compounds), were carried out before and after thermal treatment to evaluating base-flowers-mixture. The analytical indices (including microbial analysis) above described and targeted sensory evaluation test, were also organized for the prepared flower yogurt. In particular, sensorial analysis was carried out following descriptive methods . The trained panel was asked to evaluate intensity of the “new product” typical parameters, such as, color, perfume, flavor, texture, etc.
A critical aspect of the research was the difficulty to obtain and receive suitable raw material. In fact, at the moment the organic cultivation of flowers (specially organic roses destined for nutrition) doesn’t exist in Italy. Only through a special network of information (web site, etc) was it possible to find a flower producer, working organically. Other samples of organic roses were available from private collectors and agricultural research institutes involved in flower cultivation.
RIASSUNTO
Lo scopo di questa tesi di dottorato è stato quello di indagare sull’idoneità all’impiego dei fiori in termini nutraceutici, tecnologici e di salubrità per la realizzazione di un nuovo ingrediente alimentare. Come modello dello studio, è stata scelta la specie floricola Rosa sp. i cui petali, noti per la loro ricchezza in principi attivi, sono da tempo utilizzati in ambiti sia fitoterapico sia gastronomico. Tuttavia, le informazioni scientifiche disponibili sulle proprietà chimico-nutrizionali e tecnologiche dei petali di rosa, sono attualmente frammentarie proprio per l’aspetto innovativo dell’impiego ‘convenzionale’ come ingrediente alimentare. Un significativo aspetto della ricerca ha riguardato le modalità produttive della materia prima la cui coltivazione è avvenuta in un ambiente naturale e protetto senza l’utilizzo di fitofarmaci e di concimi chimici. L’indagine scientifica ha preso origine dagli studi di caratterizzazione chimica di cultivar di rose coltivate biologicamente, valutate nel corso delle operazioni tecnologiche a cui si è fatto ricorso per la produzione di un ‘intermedio’ (semilavorato) da destinare a successivi utilizzi. Attualmente non esistono in letteratura studi riguardanti le proprietà chimiche e biochimiche di preparati, ottenuti dalla lavorazione di matrici floricole (e non dai loro estratti), utilizzabili in produzioni di largo consumo come i prodotti lattiero-caseari. L’obiettivo della presente ricerca è stato quello di formulare un ingrediente ai petali di rosa per un alimento-base come lo yogurt. La produzione dello yogurt, alimento di per sé funzionale, verrebbe in tal caso diversificata proprio grazie alla nuova formulazione, caratterizzata dalle sostanze bio-attive della matrice floricola. Pertanto si sono studiate e definite le relazioni esistenti tra il processo di trasformazione tecnologica dei petali di rosa in semilavorato, la composizione di fase di quest’ultimo e le caratteristiche chimiche, microbiologiche e funzionali del nuovo ingrediente così ottenuto. Sono stati messi a punto una serie di protocolli analitici per la valutazione dei parametri chimico-nutrizionali sulla materia prima (contenuto in carboidrati solubili e in acidi organici) e dei contenuti nutraceutici. Tali contenuti sono stati analizzati sia in termini di singole molecole o di gruppi di composti antiossidanti (vitamina C, contenuto in polifenoli e antociani totali), sia in termini di attività antiradicalica espressa come potere scavenger di una molecola rappresentativa del pool antiossidante appartenente al substrato vegetale, mediante opportuni saggi (test contro i radicali DPPH e Sale di Fremy). E’ stata successivamente studiata una ‘ricetta’ per la trasformazione dei petali di rosa di alcune delle cultivar testate, in miscela-base, modulando le formulazioni base-frutta sia come quantità della materia prima utilizzata sia relativamente all’adozione del protocollo termico di stabilizzazione. Sono state messe a punto le metodiche di estrazione dei composti bio-attivi (polifenoli e antociani totali) dalla miscela-base anche dopo trattamento termico. Sono stati pertanto misurati gli indici analitici per la valutazione dello stato di conservazione (parametri di processo e contenuti microbiologici durante la shelf-life) sia per l’ingrediente sia per lo yogurt formulato. Su tale prodotto sono stati poi eseguiti dei test d’assaggio di tipo descrittivo da parte di un panel addestrato in grado di valutare l’intensità di alcuni caratteristici parametri sensoriali del nuovo prodotto.
Alcune delle criticità relative allo svolgimento di questo lavoro sono sorte in relazione al reperimento di materia prima idonea in quanto, attualmente, non sono presenti in Italia roseti biologici. L’approvvigionamento delle cultivar di rose studiate è stato possibile grazie all’individuazione di siti di raccolta non convenzionali in cui la coltivazione delle rose avveniva secondo le modalità della conduzione biologica (roseto privato, parcelle sperimentali, ambiente naturale)
Aspetti nutraceutici delle fragole : indagini sul contenuto in acido ascorbico
No full textTwenty fruit samples of 36 cvs and 16 selections grown at Cesena, Boves and Verona from 1994 to 2001 were assayed for the ascorbic acid content. Results showed a wide range of ascorbic acid content, from 20 to 100 mg/100 g f.w., according to the cultivars. Factors such as growing location, year of production and short term storage were also studied, showing large effects on ascorbic acid content
Evaluation of postharvest quality of strawberries in Italy
No full textA national project to evaluate the quality of strawberry cultivars has been running in Italy for ten years. The aim of the program is to recommend cultivars suited to different growing areas. National and foreign cultivars have been assessed for at least two years for postharvest quality, including a short storage time to simu-late conditions during export. A score of 0 to 1 (0=poor, 0.5=average, and 1=good) was assigned to each quality parameter. In the Cesena area, the cultivars ‘Alba’, ‘Kore’, ‘Cifrance’, ‘Marjolaine’, ‘Queen Elisa’, ‘Idea’ and ‘Nadina’ had the highest scores, while in the Verona area the best were ‘Thethis’, ‘Darselect’, ‘Marmolada®Onebor’ and ‘Miss’. Additionally at harvest time, a sensory test was performed on some cultivars from both areas for sweetness, acidity, aroma and firmness. In the Cesena area, ‘Dora’ was judged sweet, firm and aromatic, followed by ‘Queen Elisa’. In Verona, ‘Darselect’ had the highest aroma leve
Recupero della vecchia cv di melo Renetta ruggine di Torriana : caratterizzazione e problemi di conservabilità
No full textTrials were carried out on the old apple cv Renetta ruggine di Torriana, evaluating fruit quality and keeping quality. The storage was performed at 2 deg C both in air and in CA (1.5% O2 and 1% CO2) up to 4/6 months. The results showed a high level of internal browning, with no relation with harvesting time. In order to verify if damages were due to low temperature, new storage trials were performed at 0, 2, 4, 6 deg C in air or at 4 deg C in CA. The results showed less internal browning at temperature higher than 4 deg C
Applicazioni di test sensoriali nella valutazione della qualità organolettica delle fragole
No full textDevelopment of a headspace-solid phase micro extraction method to monitor changes in volatile profile of rose (Rosa hybrida, cv David Austin) petals during processing
No full textIn the present study, headspace solid phase microextraction combined to capillary gas chromatography (HS-SPME-GC) has been applied for the determination of changes in the volatile profile of rose petals (Rosa hybrida, cvs David Austin) following processing (heat treatment and addition as an ingredient to a food product—for example yoghurt). Four SPME fibres at two sampling temperatures (40 and 60 °C) with a sampling time of 30 min were examined. Volatile profiles were detected either by FID or/and by olfactometry (ODP-II, Gerstel). Fibre testing was performed using raw rose petals for sampling temperature selection and an 18 characteristic rose volatile standard mixture in water was used to compare fibre performances at the sampling temperature of 60 °C. Polydimethylsiloxane-divinylbenzene (PDMS-DVB) fibre at the sampling temperature of 60 °C was the most suitable to sample the rose alcohols phenyl ethanol, citronellol, nerol, geraniol and eugenol, as assessed by GC-olfactometry, not only from raw petals, but also from processed rose petals and the food product. PDMS-DVB fibre also showed a desired low affinity to volatiles from yoghurt, which reduces the influence of food matrix on the volatile profile. The method was linear over two orders of magnitude and had satisfactory repeatability, with limits of detection for the rose alcohols ranging from <1 to 10 ng/ml concentration levels
Evaluation of fruit aroma quality : comparison between gas chromatography-olfactometry (GC-O) and odour activity value (OAV) aroma patterns of strawberries
No full textGas chromatography-olfactometry (GC-O) is based on the use of human assessors as a sensitive and selective detector to ascertain odour-active volatile compounds in a sample extract, whereas odour intensity value (OAV) determination is widely used to obtain odour patterns starting from quantitative compositions. Whether there is an exact parallelism between odour patterns obtained from GC-O parameters and OAV is not yet well investigated. To this aim, the OAV and GC-O odour patterns of six strawberry genotypes were compared. Esters represented 97.9-99.8% of total volatiles, with methyl butanoate being the main Compound; dimethyl disulfide, dimethyl trisulfide, gamma-heptalactone and delta-decalactone were detected only by GC-O. OAV indicated that 25 volatiles out of 39 could actually contribute to the odour pattern, while the GC-O sensory panel perceived 30 odorous events. The major odour contributors in OAV and the maximum odour intensities of odour events in GC-O were genotype dependent. Comparing OAV with GC-O patterns, the spatial relationships in principal component analysis biplots were comparable: 'VR4' was opposed to 'Alba' and 'CS4', and 'Dora' to 'Darselect' and 'Eva'. GC-O and OAV resulted in comparable strawberry odour patterns, GC-O giving the most detailed qualitative and quantitative description. However, being GC-O, a time-consuming method, it should not be routinely used
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