Influence of quality attributes of early, intermediate and late peach varieties on suitability for fresh-convenience products

Fresh convenience products represent a category of minimally processed fruit and vegetables (chunks, mousse, smoothies) that respond to the changes in consumer attitudes. Thanks to the image of convenience (time-saving, snack sizes, no waste, smart packaging) and healthiness their sales are steadily increasing. In this study 26 varieties (including peach, nectarines, and clingstone peaches) from Apulian production were divided into three groups according to harvest dates in early (A), middle (B) and late (C) maturing. Physical, chemical and sensorial analyses were performed in order to select high quality fruits for minimal processing according to the harvesting season. A multivariate Principal Component Analysis was applied to discriminate different varieties for quality attributes. Within Group A, ‘Honey Kist’ showed the lowest acidity and intermediate susceptibility to mechanical damage. For Group B, ‘Stark Red Gold’, ‘Zee Glo’ and ‘Venus’ resulted different in sensorial evaluation, while ‘Loadel’ and ‘Eolia’ were more susceptible to browning. For Group C, ‘Tardi Belle’ and ‘Baby Gold7’, although more sensitive to mechanical damage, were differentiated for flavor. Results of this work confirm the extreme variability among varieties in terms of sensorial quality, susceptibility to browning and to mechanical damage, and the importance of assessing varietal screening for selection of most suitable varieties for minimal processing

Effect of type of fertilization and maturity on quality of fresh-cut red and yellow peppers (Capsicum annuum L.)

The aim of this work was to evaluate the effect of the type of fertilization (mineral and combined fertilization with compost in pre-transplant plus mineral addition during cultivation) and stage of maturity at harvest (mature-green and full-colored) on post-cutting quality of red and yellow ‘Cazzone’ peppers. Peppers were cut into strips, and air-stored for 8 days at 5°C. During storage, color, appearance score, firmness, respiration rate, soluble solids, acidity, pH, vitamin C, total phenols, and antioxidant activity were measured. The maturity stage influenced color parameters and soluble solids, acidity and pH for both yellow and red types. Full-colored peppers showed a lower respiration rate, and higher SSC than mature-green peppers; for the yellow type, a lower firmness value was observed for full-colored fruits compared to the mature-green ones. A lower antioxidant activity was also observed in the yellow type fertilized with the combined treatment, while phenol content in full-colored peppers was higher than in mature-green ones. Fresh-cut yellow peppers showed higher susceptibility to decay compared to red types: after 8 days of storage, the appearance score in mineral fertilized full-colored yellow peppers dramatically decreased below the limit of marketability. The results of this experiment show that the type of fertilization and maturity stage can have varying impact on the quality of yellow and red peppers

Detection and enumeration of Listeria monocytogenes in fresh cut vegetables using MPN-Real-Time PCR

Listeria monocytogenes is a gram positive, rod shaped, pathogenic bacterium, causative agent of a severe infection generally known as listeriosis. Packaging and storage conditions of fresh cut vegetables may favour the growth of this psychrotrophic pathogen leading to potential health threat. Detection and enumeration of L. monocytogenes in concentrations up to 103 CFU/g, usually implies use of the most-probable-number technique (MPN) which may take up to seven days for verified identification of the pathogen. We developed a fast and reliable protocol combining MPN with a Real-Time quantitative PCR (qPCR) approach. Samples of fresh cut salads (25 g) purchased at local shops were spiked with 1 to 105 CFU/g of L. monocytogenes. Samples were homogenized, and triplicate series of tubes containing 10-5 to 10 g of food were incubated in Fraser broth at 30\ub0C for 48 h for standard MPN analysis. After incubation, broth samples were taken from each tube and DNA was extracted. DNA from enrichment tubes was used as template in a qPCR assay targeting a 64 bp hlyA gene sequence of L. monocytogenes. Results of this assay were than compared with those of standard MPN analysis and a complete accordance was observed. Furthermore, we tested an enrichment free approach using the same qPCR assay. Samples were prepared as described for MPN-qPCR while DNA extraction was performed prior to enrichment of inoculated salads. This approach allowed us to identify L. monocytogenes in samples spiked with 10-105 CFU/g. The whole process, including DNA extraction, required less than four hours, thus providing a fast and reliable tool for detection of L. monocytogenes in fresh cut vegetables

Longitudinal variation of amino acid levels in human milk and their associations with infant gender

It is discussed that specific amino acids (AAs) have functional roles in early life. Understanding the AA composition in human milk (HM) during lactation assists in specifying these roles. To this end we assessed the levels of free AAs (FAAs), total AAs (free and bound, TAAs) and protein levels in HM in the first 6 months of lactation, and evaluated possible associations with infant gender. HM samples of 25 healthy Dutch mothers participating in the PreventCD study were collected monthly during the first 6 months of lactation. Of the participating mothers, 12 gave birth to a boy and 13 gave birth to a girl. Analyses of the HM samples revealed that levels of free glutamate, glutamine, aspartate, glycine, and serine significantly increased during months 1–3 of lactation, both in absolute sense and relative to TAA levels. Evaluation of gender differences by mixed model analyses revealed an association between female infant gender and higher protein content (p = 0.0465) and TAA content (p = 0.0362) in HM during the first 3 months of lactation. Furthermore, there was a tendency for an association of male infant gender with higher levels of free glutamine (p = 0.0948) in HM during the first 3 months of lactation. These results show that FAA, TAA and protein levels in HM display a time-specific occurrence during lactation. Moreover, although confirmation is necessary in view of the small sample size, this study indicates that the AA composition in HM shows differential effects of the infant’s sex

Le macchine utilizzate per la lavorazione dei prodotti della IV gamma

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Modelling sensorial and nutritional changes to better define quality and shelf life of fresh-cut melons.

The shelf life of fresh-cut produce is mostly determined by evaluating the external appearance since this is the major factor affecting consumer choice at the moment of purchase. The aim of this study was to investigate the degradation kinetics of the major quality attributes in order to better define the shelf life of fresh-cut melons. Melon pieces were stored for eight days in air at 5°C. Sensorial and physical attributes including colour, external appearance, aroma, translucency, firmness, and chemical constituents, such as soluble solids, fructose, vitamin C, and phenolic content, along with antioxidant activity were monitored. Attributes showing significant changes over time were used to test conventional kinetic models of zero and first order, and Weibullian models. The Weibullian model was the most accurate to describe changes in appearance score, translucency, aroma, firmness and vitamin C (with a regression coefficient always higher than 0.956), while the other parameters could not be predicted with such accuracy by any of the tested models. Vitamin C showed the lowest kinetic rate among the model parameters, even though at the limit of marketability (appearance score 3), estimated at five days, a loss of 37% of its initial content was observed compared to the fresh-cut product, indicating a much lower nutritional value. After five days, the aroma score was already 2.2, suggesting that this quality attribute, together with the vitamin C content, should be taken into account when assessing shelf life of fresh-cut melons. In addition, logistical models were used to fit the percentage of rejected samples on the basis of non-marketability and non-edibility (appearance score <3 and <2, respectively). For both parameters, correlations higher than 0.999 were found at P<0.0001; for each mean score this model helps to understand the distribution of the samples among marketable, nonmarketable, and non-edible products