Low-frequency, high-power ultrasound treatment at different pressures for olive paste: Effects on olive oil yield and quality.

Ultrasound technology was employed to test its action on the extraction of olive oil at the industrial scale. Because of its mechanical effects, ultrasound waves were applied to the olive paste, between the crushing and malaxing operations. Comparative experiments were performed between traditional extraction processes and the innovative extraction process, with the addition of the ultrasound treatment. Different levels of pressure were tested on olive paste, using four different olive cultivars. Pressure level played an important role in olive oil extractability. When ultrasound was subjected to olive paste with a pressure of about 3.5 bar, there was a significant increase of extractability compared to the traditional process. On the other hand, there was no significant effect between ultrasound treatment and traditional technology on extractability when ultrasound at a pressure level of 1.7 bar was used.

Sensory and chemical profile of a phenolic extract from olive mill waste waters in plant-base food with varied macro-composition.

Phenols from olive mill waste water (OMWW) represent valuable functional ingredients. The negative impact on sensory quality limits their use in functional food formulations. Chemical interactions phenols/biopolymers and their consequences on bioactivity in plant-base foods have been widely investigated, but no studies to date have explored the variation of bitterness, astringency and pungency induced by OMWW phenols as a function of the food composition. The aim of the paper was to profile the sensory and chemical properties of phenols from OMWW in plant-base foods varied in their macro-composition. Four phenol concentrations were selected (0.44, 1.00, 2.25, 5.06 g/kg) to induce significant variations of bitterness, sourness, astringency and pungency in three plant-base food: proteins/neutral pH - bean purée (BP), starch/neutral pH - potato purée (PP), fiber/low pH - tomato juice (TJ). The macro-composition affected the amount of the phenols recovered from functionalized food. The highest recovery was from TJ and the lowest from BP. Two groups of 29 and 27 subjects, trained to general Labelled Magnitude Scale and target sensations, participated in the evaluation of psychophysical curves of OMWW phenols and of functionalized plant-base foods, respectively. Target sensations were affected by the food macro-composition. Bitterness increased with phenol concentration in all foods. Astringency and sourness slightly increased with concentration, reaching the weak-moderate intensity at the highest phenol concentration in PP and TJ only. Pungency was suppressed in BP and perceived at weak-moderate intensity in PP and TJ sample at the highest phenol concentration. Proteins/neutral pH plant-food (BP) resulted more appropriate to counteract the impact of added phenol on negative sensory properties thus allowing to optimize the balance between health and sensory properties.

Effect on quanti-quality milk and mozzarella cheese characteristics with further increasing the level of dried stoned olive pomace in diet for lactating buffalo.

OBJECTIVE: Following a previous report, an experiment was conducted to determine the effect of increasing level of dried stoned olives pomaces (DSOP) in the diet of lactating buffaloes on milk and mozzarella cheese yield and characteristics. METHODS: Sixteen pluriparous buffaloes distributed into two groups were fed an isoenergetic (0.9 milk forage unit/kg) and isoprotein (149 g/kg dry matter [DM] of crude protein) diet, with or without DSOP. Each animal received 17 kg DM/d. Samples of forages and concentrates were weekly collected and used for duplicate chemical analyses. Individual milk samples from each control were analyzed for chemical and coagulating parameters and daily production of mozzarella cheese was estimated. At the end of the trial, bulk milk of each group was processed to produce mozzarella cheese and chemical (fat, protein, ash, pH) composition, fatty acids composition, carotenoids and tocopherols content were determined. A sensory test was also performed. The oxidative stability was measured on mozzarella cheese and on governing liquid. RESULTS: No significant differences were observed, neither for milk yield and body condition score, nor for milk characteristics. The fat was higher (p<0.05) in mozzarella of DSOP fed group but, saturated fatty acids were lower and unsaturated higher (p<0.01). Furthermore, lower atherogenic (p<0.01), and thrombogenic (p<0.05) indices were found in mozzarella cheese of DSOP fed group. In addition, the administration of DSOP did not affect the mozzarella cheese oxidative stability and no negative effect was found in the sensory properties. CONCLUSION: No contraindications appeared for the inclusion of DSOP in the diet of lactating buffaloes. Besides, important effects on mozzarella cheese quality were obtained, such as a modification of fat content and attributes with an increment in the mono-unsaturated. Additionally, a lower saturated/unsaturated ratio and atherogenic and thrombogenic indices suggest an improvement of dietetic and nutritional characteristics of mozzarella cheese.

Cooling treatment of olive paste during the oil processing: Impact on the yield and extra virgin olive oil quality.

In recent years, the temperature of processed olives in many olive-growing areas was often close to 30°C, due to the global warming and an early harvesting period. Consequently, the new trends in the extraction process have to include the opportunity to cool the olives or olive paste before processing to obtain high quality EVOO. A tubular thermal exchanger was used for a rapid cooling treatment (CT) of olive paste after crushing. The results did not show a significant difference in the oil yield or any modifications in the legal parameters. The cooling process determined a significant improvement of phenolic compounds in all the three Italian cultivar EVOOs analyzed, whereas the volatile compounds showed a variability largely affected by the genetic origin of the olives with C6 aldehydes that seem to be more stable than C6 alcohols and esters.

Effect of an olive phenolic extract on the quality of vegetable oils during frying.

The potential of a phenolic extract (PE) from olive vegetation water (OVW) to limit the negative effects of frying was tested after adding it at different concentrations to a refined olive oil (RO). Its efficacy was also compared to ROs containing butylated hydroxytoluene (BHT) and an extra virgin olive oil (EVOO) with a high polyphenol content. Analyses of the oils collected after 30min, 1, 2, 4, 6, 8, 10 and 12h of frying at 180°C, demonstrated that degradation of the polyphenols was proportional to the original content; at a concentration of at least 400mg/kg of polyphenols, PE was able to reduce oxidation of the tocopherols and the emission of low-molecular-weight aldehydes better than BHT and with similar results to the EVOO. In addition, secoiridoid oxidative compounds were examined by high-performance liquid chromatography/triple quadrupole tandem mass spectrometry with electrospray ionisation.

Dietary olive cake reduces the oxidation of lipids, including cholesterol, in lamb meat enriched in polyunsaturated fatty acids.

Over 40 days, lambs were fed: concentrate (C), concentrate containing 20% linseed (L), concentrate containing 35% olive cake (OC), or concentrate containing 10% linseed and 17% olive cake (OCL). The polyunsaturated fatty acids (PUFA) and peroxidation index (PI) in phospholipids were increased by the L and OCL treatments (P=0.007 and P=0.003, respectively). The OC and OCL diets increased the concentration of tocopherol in muscle (P<0.001). Compared to the OC and OCL diet, the L diet increased fatty acid oxidation, measured as conjugated dienes (CD; P=0.003), peroxides (PV; P<0.001) and TBARS (P=0.002) in minced muscle over 11 days of storage in high-oxygen atmosphere. Also, the L diet increased (P<0.001) the levels cholesterol oxidation products (COPs). In conclusion, feeding olive cake improved the oxidative stability of lamb meat and the combination of olive cake and linseed improved the fatty acid composition of meat without compromising its oxidative stability.

Use of dried stoned olive pomace in the feeding of lactating buffaloes: effect on the quantity and quality of the milk produced.

Dried stoned olive pomace (DSOP) was administered to dairy water buffaloes, and their productive performance and milk composition were analysed. Sixteen pluriparous lactating buffaloes were divided into two uniform groups (control and experimental), taking into consideration the following parameters: milk production (2,192 and 2,102 kg) and duration of lactation (254 and 252 d) of the previous year, distance from calving (51 and 43 d), milk production (9.71 and 10.18 kg/d), body condition score (BCS) (6.44 and 6.31) and weight (617 and 653 kg) at the beginning of the trial. Both diets had the same formulation: second cut alfalfa hay 20%, corn silage 42%, concentrate 38% but the two concentrates differed in their formulation, the experimental one contained 15.50% of DSOP as fed. The employed DSOP showed high amounts of secoiridoids, such as 3,4-dihydroxyphenylethanol (3,4-DHPEA) (1.2 g/kg DM), 3,4-dihydroxyphenylethanol-elenolic acid di-aldehyde (3,4-DHPEA-EDA) (12.6 g/kg DM), p-hydroxyphenylethanol-elenolic acid di-aldehyde (p-HPEA-EDA) (5.6 g/kg DM) and lignans, which are known to be powerful bioactive compounds. The control diet had an energy-protein content of 0.86 Milk FU/kg DM and 143.3 g/kg DM of crude protein, whereas the experimental diet of 0.87 Milk FU/kg DM and 146.6 g/kg DM of crude protein. Each animal of the two groups received 17 kg DM/d and each buffalo of the experimental group, by way of the concentrate, ingested 1.05 kg DM/d of DSOP. The trial lasted 40 days. No significant difference was found between the BCS (6.41 and 6.53), live weight (625.93 and 662.50 kg) and milk production (9.69 and 10.08 kg/d) of the two groups, as was the case for fat, protein, lactose, pH and coagulating parameters of the two milks. The milk fat of the experimental group had a significantly higher content of total tocopherols (10.45 vs 8.60 µg/g, p<0.01) and retinol (3.17 vs 2.54 µg/g, p<0.01). The content of the reactive substances with tiobarbituric acid (TBARs) was significantly lower in the milk fat of the experimental group (12.09 vs 15.05 µg MDA/g, p<0.01). The acid content of the milk fat of the experimental group had a significantly higher content (p<0.05) of C18:0 and of C18:3ω6. LC-MS/MS analysis showed the presence of 3,4-DHPEA (36.0 µg/L) in the milk of the DSOP-fed buffaloes, while other phenols were not found. DSOP, in the quantity utilized, can be used in the feeding of the lactating buffalo; the dietetic-nutritional characteristics of the milk are improved due to a greater contribution of tocopherols, retinol and the presence of hydroxytyrosol.

Effect of dietary supplementation with olive pomaces on the performance and meat quality of growing rabbits.

The aim was to investigate the effects of three types (A, B and C) of stoned and dehydrated olive pomaces (OPs), differing in olive cultivar, on productive performance and meat quality of growing rabbits. The inclusion of OPs (5%) negatively affected the performance of rabbits as it reduced the feed intake, growth rate, carcass weight and dressing out percentage (P<0.05). Compared with the control, the meat of OP rabbits had a greater amount of monounsaturated and a lower amount of polyunsaturated fatty acids (P<0.05), independent of the type of OP used. Oxidative processes in the meat of OPA and OPB were higher (P<0.05), whereas OPC showed the same levels as the control group. This was due to the higher total polyphenol concentration and to the concomitant lower peroxide value of OPC. These results recommend the use of OP in rabbit diet with caution, taking into account the quality of the by-product in terms of oxidative status.

Functional milk beverage fortified with phenolic compounds extracted from olive vegetation water, and fermented with functional lactic acid bacteria.

Functional milk beverages (FMB100 and FMB200) fortified with phenolic compounds (100 and 200mg/l) extracted from olive vegetable water, and fermented with γ-amino butyric acid (GABA)-producing (Lactobacillus plantarum C48) and autochthonous human gastro-intestinal (Lactobacillus paracasei 15N) lactic acid bacteria were manufactured. A milk beverage (MB), without addition of phenolic compounds, was used as the control. Except for a longer latency phase of FMB200, the three beverages showed an almost similar kinetic of acidification, consumption of lactose and synthesis of lactic acid. Apart from the beverage, Lb. plantarum C48 showed a decrease of ca. Log 2.52-2.24 cfu/ml during storage. The cell density of functional Lb. paracasei 15N remained always above the value of Log 8.0 cfu/ml. During fermentation, the total concentration of free amino acids markedly increased without significant (P > 0.05) differences between beverages. The concentration of GABA increased during fermentation and further storage (63.0 ± 0.6-67.0 ± 2.1mg/l) without significant (P > 0.05) differences between beverages. After fermentation, FMB100 and FMB200 showed the same phenolic composition of the phenol extract from olive vegetable water but a different ratio between 3,4-DHPEA and 3,4-DHPEA-EDA. During storage, the concentrations of 3,4-DHPEA-EDA, p-HPEA and verbascoside of both FMB100 and FMB200 decreased. Only the concentration of 3,4-DHPEA increased. As shown by SPME-GC-MS analysis, diactetyl, acetoin and, especially, acetaldehyde were the main volatile compounds found. The concentration of phenolic compounds does not interfere with the volatile composition. Sensory analyses based on triangle and paired comparison tests showed that phenolic compounds at the concentrations of 100 or 200mg/l were suitable for addition to functional milk beverages.

Phenolic compounds in olive oil: antioxidant, health and organoleptic activities according to their chemical structure.

Hydrophilic phenols are the most abundant natural antioxidants of virgin olive oil (VOO), in which, however, tocopherols and carotenes are also present. The prevalent classes of hydrophilic phenols found in VOO are phenolic alcohols and acids, flavonoids, lignans and secoiridoids. Among these substances the last two classes include the most concentrate phenols of VOO. Secoiridoids, like aglycone derivatives of oleuropein, demethyloleuropein and ligstroside, are present in olive fruit as most abundant VOO phenolic antioxidants. Several important biological properties (antioxidant, anti-inflammatory, chemopreventive and anti-cancer) and the characteristic pungent and bitter tasty properties have been attributed to VOO phenols. Relationships between polyphenols activities and their chemical structures are discussed in this paper.

Cancer chemoprevention by hydroxytyrosol isolated from virgin olive oil through G1 cell cycle arrest and apoptosis.

Recent epidemiological evidence and animal studies suggest a relationship between the intake of olive oil and a reduced risk of several malignancies. The present study assesses the effect of hydroxytyrosol, a major antioxidant compound of virgin olive oil, on proliferation, apoptosis and cell cycle of tumour cells. Hydroxytyrosol inhibited proliferation of both human promyelocytic leukaemia cells HL60 and colon adenocarcinoma cells HT29 and HT29 clone 19A. The con-centrations of hydroxytyrosol which inhibited 50% of cell proliferation were approximately 50 and approximately 750 micromol/l for HL60 and both HT29 and HT29 clone 19A cells, respectively. At concentrations ranging from 50 to 100 micromol/l, hydroxytyrosol induced an appreciable apoptosis in HL60 cells after 24 h of incubation as evidenced by flow cytometry, fluorescence microscopy and internucleosomal DNA fragmentation. Interestingly, no effect on apoptosis was observed after similar treatment of freshly isolated human lymphocytes and polymorphonuclear cells. The DNA cell cycle analysis, quantified by flow cytometry, showed that the treatment of HL60 cells with hydroxytyrosol 50-100 micromol/l arrested the cells in the G0/G1 phase with a concomitant decrease in the cell percentage in the S and G2/M phases. These results support the hypothesis that hydroxytyrosol may exert a protective activity against cancer by arresting the cell cycle and inducing apoptosis in tumour cells, and suggest that hydroxytyrosol, an important component of virgin olive oil, may be responsible for its anticancer activity.

Effect of enzyme treatment during mechanical extraction of olive oil on phenolic compounds and polysaccharides.

The effect of the use of cell-wall-degrading-enzyme preparations during the mechanical extraction process of virgin olive oil on the phenolic compounds and polysaccharides was investigated. The use of the enzyme preparations increased the concentration of phenolic compounds in the paste, oil, and byproducts. Especially, the contents of secoiridiod derivatives such as the dialdehydic form of elenolic acid linked to 3,4-dihydroxyphenylethanol (3,4-DHPEA-EDA) and an isomer of oleuropein aglycon (3,4-DHPEA-EA), which have high antioxidant activities, increased significantly in the olive oil. Furthermore, the use of an N(2) flush during processing strongly increased the phenolic concentration. Analyses of the pectic polymers present in the paste showed that the use of pectinolytic enzyme preparations increased the yield of the buffer soluble pectins and the proportion of molecules with a lower molecular mass. Also, the content of uronic acids in the buffer soluble extract increased considerably due to the use of the enzyme preparations. Analysis of the polymeric carbohydrates in the vegetation waters showed the presence of mainly pectic polymers. The addition of commercial enzyme preparations increased the uronic acid content of the polysaccharides in the vegetation water substantially compared to the blank. This study showed that the addition of cell-wall-degrading enzymes did improve the olive oil quality; however, mechanisms remained unclear.

Phenolic compounds of olive fruit: one- and two-dimensional nuclear magnetic resonance characterization of Nüzhenide and its distribution in the constitutive parts of fruit.

The phenolic composition of peel, pulp, and seed of the olive fruit was studied for several Italian cultivars used for oil extraction. The seed contained a compound never previously detected in peel and in pulp. The spectroscopic characterization of this compound proved, for the first time, the presence of nüzhenide in the olive seed. Study of the phenolic composition showed that oleuropein, demethyloleuropein, and verbascoside were present in all of the constitutive parts of the fruit; by contrast, nüzhenide was exclusively present in the seeds of all the cultivars at all ripening stages studied.

Gustatory and food habit changes during the menstrual cycle.

Gustatory and food habit changes during the menstrual cycle were studied in 8 women, 6 smokers and 2 non-smokers, aged 23-37 years. The following parameters were evaluated during three consecutive menstrual cycles: blood oestradiol and progesterone levels on the 7th, 14th and 21st day of each cycle (radioimmunoassay); detection and recognition thresholds and concentration preferences for sucrose, sodium chloride, citric acid and quinine sulphate on the 1st, 7th, 14th and 21st day of each cycle; food consumption (weighed record) on days 1 and 2, 6-8, 13-15 and 20-22 each cycle. The four basic tastes were influenced differently by blood hormone levels during the menstrual cycle. Sensitivity to sweet taste increased with an increase of oestradiol, while sensitivity to bitter taste increased with an increase of progesterone. No correlations between hormone levels and acid taste, and only a few correlations for salt taste were found. Food habits changed during the cycle particularly for meat and fruit. Vegetables and cereals showed only a tendency to vary. In correspondence with the highest oestradiol values there was a tendency towards lower energy intake, -122 kcal (-0.51 MJ) = 8%, predominantly provided by carbohydrates (as bread).