Ella Pagliarini

Influence of dietary fat, on fatty acid composition and sensory properties of dry-cured Parma ham.

A feeding trial with 27 pigs was performed in order to estimate the effect of different dietary fats on the fatty acid composition, flavour and sensory properties of dry-cured Parma hams, ripened for 16 months. The animals received a pelleted diet supplemented with different fat sources: tallow (TA), corn oil (CO), and rapeseed oil (RO). The sensory quality of the hams was evaluated by means of sensory analyses and by instrumental procedures such as gas chromatography-mass spectrometry of the volatile aroma compounds. A treatment effect was detected for linolenic acid in RO vs. CO and TA hams (P<0.01) and for MUFA content (P<0.01) that was higher in RO and TA compared with CO. The results of panel test showed a significant difference (P<0.05) between TA vs. CO and RO hams. Volatile compounds showed limited differences even if in CO group the amount of singular compound is higher than TA and RO.

Characterization and differentiation of Italian Parma, San Daniele and Toscano dry-cured hams: a multi-disciplinary approach.

This study aimed at characterizing the sensory quality of Italian PDO dry-cured Parma, San Daniele and Toscano hams, applying a multi-disciplinary approach. Ham sensory profile as well as physico-chemical, aromatic, morphological and textural characteristics was investigated. There was a great difference between Toscano ham and Parma and San Daniele hams, which were more similar even though differentiated. Toscano ham showed higher scores for pork-meat odor, saltiness, dryness, fibrousness and hardness; accordingly, this ham was described by a high NaCl content and by high values of instrumental hardness, cohesiveness, gumminess and chewiness. Parma ham was characterized by a cured flavor, whereas San Daniele ham showed a wider fatty area and higher pH values. Parma and San Daniele hams were also described by higher values of sweetness, RGB color values and water activity. Sensory characteristics evaluated by trained assessors were correlated to instrumental measures, indicating that instrumental devices can be effectively applied for dry-cured ham characterization.

Optimisation of extra virgin Olive Oil quality

This study investigated the correlation between total polyphenol content and the stability (ie induction time by Rancimat) of oil samples according to different regions, cultivars, extraction technologies and ripening times of raw material. Results indicate a correlation of oil stability with total polyphenols, (r=0·88), a chemical variable easy to determine. We have set up an oil quality index as a measure of desirability including legal parameters, especially the Council Olive Oil International score (COI Score), stability (phenol content) and process yield into account. The study of the effects of olive ripening and storage prior to processing and olive paste mixing times and temperatures on the quality index using an experimental factorial design (24) were investigated. The process variables selected in the experimental factorial design were studied and the main effects on desirability were identified. Based on this information, the extraction process was optimised for quality index in relation to fruit ripening and olive paste mixing time using a response contour to identify optimal experimental conditions. This innovative procedure shows that process conditions can be optimised as a function of Dtot, evaluated according to scientific determinations.

Modelling the effects of thermal sterilization on the quality of tomato puree

Abstract The aim of this work was to study and to model the effects of time-temperature conditions for sterilization on the overall quality of tomato puree. Tomato puree was produced from raw tomatoes in a pilot plant. Three sterilization tests were carried out at 90, 95 and 100 °C to obtain kinetic constants of quality properties. Heat and oxidative damage was observed in samples throughout sterilization. The furosine content increased, both the ascorbic acid content and the antioxidant activity of the hydrophilic fraction decreased, and a variation in colour (ΔE) occurred. No significant variations were found in the lycopene content, antioxidant activity of lipophilic fraction and sensory descriptors. Data were processed to obtain the relevant reaction kinetic constants, and a mathematical model was set up, which was able to predict quality variations in tomato puree during sterilization both under isothermal and non-isothermal conditions. The model was applied as a chart for optimization of sterilization.

Study of the stability of dried tomato halves during shelf‐life to minimise oxidative damage

Optimal operating conditions for storage of dried tomato halves were investigated to obtain decreased oxidative damage, evaluated in terms of colour variation, combined with microbial stability of the product, ie inhibition of growth of eumycetes. Experiments were planned using a saturated factorial design. Variables studied were the moisture content of dried tomato halves in the range 10- 60%, temperature in the range 5-30 °C and storage time in the range 1-38 days. Eighteen storage experiments were carried out in the dark under vacuum at the storage conditions indicated by the experimental design. At the end of each experiment, surface colour was measured by a tristimulus colorimeter, and growth of eumycetes was evidenced by olfactory and visual perception, followed by qualitative microbial analysis. Eumycetes were present in all stored products, except that at 10% moisture, and, generally speaking, storage conditions did not allow micro-organisms to grow. From isoresponse curves the optimal region for storage to minimise oxidative damage was extrapolated, which was represented by residual moisture values between 20 and 40% and 18 °C storage tem- perature, with a minimum point of colour variation at approximately 30% moisture content and 10 °C. # 2000 Society of Chemical Industry

A study of surface hydrophobicity of milk proteins during enzymic coagulation and curd hardening.

The formation of hydrophobic sites on the surface of casein micelles as a consequence of rennet action has been followed through the binding rate of a fluorescent probe and its distribution between a free and an ‘aggregated’ protein fraction. The variation of this parameter has been related to clotting time and curd hardening kinetics. Results show that a first aggregation of casein through hydrophobic sites interaction began as soon as rennet was added to milk. At the natural pH of milk, the sol-gel transition occurred when all the casein micelles were already involved in large aggregates. This was not the case with slightly acidified milk (pH 6·5 and 6·3) where clotting occurred well before the first aggregation step had been completed. The surface hydrophobicity of casein continued to increase in the curd due to continuing enzymic action and structural rearrangements. When this process has been completed the hardening of curd proceeds at an accelerated pace until it reached its maximum asymptotic value.

Taste sensitivity, nutritional status and metabolic syndrome: Implication in weight loss dietary interventions

AIM We investigated the relationship between taste sensitivity, nutritional status and metabolic syndrome and possible implications on weight loss dietary program. METHODS Sensitivity for bitter, sweet, salty and sour tastes was assessed by the three-Alternative-Forced-Choice method in 41 overweight (OW), 52 obese (OB) patients and 56 normal-weight matched controls. OW and OB were assessed also for body composition (by impedence), resting energy expenditure (by indirect calorimetry) and presence of metabolic syndrome (MetS) and were prescribed a weight loss diet. Compliance to the weight loss dietary program was defined as adherence to control visits and weight loss ≥ 5% in 3 mo. RESULTS Sex and age-adjusted multiple regression models revealed a significant association between body mass index (BMI) and both sour taste (P < 0.05) and global taste acuity score (GTAS) (P < 0.05), with lower sensitivity with increasing BMI. This trend in sensitivity for sour taste was also confirmed by the model refitted on the OW/OB group while the association with GTAS was marginally significant (P = 0.06). MetS+ subjects presented higher thresholds for salty taste when compared to MetS- patients while no significant difference was detected for the other tastes and GTAS. As assessed by multiple regression model, the association between salty taste and MetS appeared to be independent of sex, age and BMI. Patients continuing the program (n = 37) did not show any difference in baseline taste sensitivity when compared to drop-outs (n = 29). Similarly, no significant difference was detected between patients reporting and not reporting a weight loss ≥ 5% of the initial body weight. No significant difference in taste sensitivity was detected even after dividing patients on the basis of nutritional (OW and OB) or metabolic status (MetS+ and MetS-). CONCLUSION There is no cause-effect relationship between overweight and metabolic derangements. Taste thresholds assessment is not useful in predicting the outcome of a diet-induced weight loss program.

Determinants of Obesity in Italian Adults: The Role of Taste Sensitivity, Food Liking, and Food Neophobia

Recent evidence has suggested that factors related to sensory perception may explain excess weight. The objective of this study was to consider multiple aspects while investigating the phenomenon of obesity. One goal was to compare taste acuity (taste threshold and density of fungiform papillae) in both normal weight and obese subjects. Thresholds for 4 basic tastes and the fat stimulus were investigated. A second research goal was to study the relationship between food neophobia and food liking according to the body mass index and taste sensitivity. The results showed that obese subjects seem to have higher threshold values and a reduced number of fungiform papillae than do normal weight subjects. Food neophobia did not vary with nutritional status, whereas differences were found for food liking, with obese subjects showing significantly higher liking ratings for high energy dense products compared with normal weight subjects.

Sensory descriptors, hedonic perception and consumer’s attitudes to Sangiovese red wine deriving from organically and conventionally grown grapes

In recent years, produce obtained from organic farming methods (i.e., a system that minimizes pollution and avoids the use of synthetic fertilizers and pesticides) has rapidly increased in developed countries. This may be explained by the fact that organic food meets the standard requirements for quality and healthiness. Among organic products, wine has greatly attracted the interest of the consumers. In the present study, trained assessors and regular wine consumers were respectively required to identify the sensory properties (e.g., odor, taste, flavor, and mouthfeel sensations) and to evaluate the hedonic dimension of red wines deriving from organically and conventionally grown grapes. Results showed differences related mainly to taste (sour and bitter) and mouthfeel (astringent) sensations, with odor and flavor playing a minor role. However, these differences did not influence liking, as organic and conventional wines were hedonically comparable. Interestingly, 61% of respondents would be willing to pay more for organically produced wines, which suggests that environmentally sustainable practices related to wine quality have good market prospects.

Design and setting up of a water vapour pressure capacitance manometer for measurement of water activity

Abstract Water activity (a w ) plays an essential role in food science and technology in optimizing processes (i.e. drying) and evaluating the microbiological, chemical and physical stability of foods. Accurate and precise measurement of a w is also required in view of the new trend to minimal processing of foods. A thermostated vapour pressure capacitance manometer (VPM) apparatus, based on the theory of Benado and Rizvi, was designed and built. It consisted of two flasks, one for sample and another for desiccant (CaSO 4 ), connected by means of two solenoid valves to a tubing manifold, connected to a pressure transducer, and to a vacuum pump by means of a solenoid valve. Reference samples (i.e. pure water, saturated salt solutions and microcrystalline cellulose at different moisture contents) were used to validate the VPM at 25 °C. Results showed an accuracy of ±0.01 a w and a standard deviation of ±0.01 a w . Based on this study, the evacuation time and the time of sample equilibrium after evacuation were identified as the two critical points of the VPM for accurate measurements.