Noni (Morinda citrifolia L.) fruit as a new source of milk-clotting cysteine proteases.

This work reports the characterisation of caseinolytic and milk-clotting activities of proteases extracted from ripe fruits of Morinda citrifolia L., as a potential of their use in cheese production. Noni puree extract (NPE) was obtained by homogenising the fresh puree in 150 mM NaCl/50 mM sodium phosphate buffer (pH 7.0). The resulting protein concentration was of 0.367 ±â€¯0.006 mg/mL, and an electrophoretic profile of the extract revealed protein bands ranging from 14 to 55 kDa. The proteolytic activity of NPE was higher when the extract had been previously incubated at pH 6.0 (8.859 ±â€¯0.216 U/mg), whereas the optimum caseinolytic activity was observed at 50 °C. Noni puree proteases were strongly (98%) inhibited by iodoacetamide and E-64, suggesting the presence of only cysteine proteases in the crude extract. NPE proteases showed a milk-clotting activity (MCA) of 238.80 ±â€¯5.29 U/mL, a specific milk-clotting activity (SMCA) of 9950.17 ±â€¯220.74 U/mg, and an SMCA/PA ratio of 1124.31 ±â€¯24.94, this last being comparable to those of commercial calf rennet. The cheese manufactured using NPE presented brittle and soft texture, high humidity, and showed sanitary conditions compatible with current Brazilian regulations. The product showed a slightly bitter taste, but still good acceptability, rating between 6 and 7 in the hedonic scale for flavour, texture, and overall acceptance. Lastly, there was 60% of positive purchase intent, demonstrating that noni fruit is a promising source of milk-clotting enzymes for the dairy industry.

Optimization of headspace solid phase micro-extraction of volatile compounds from papaya fruit assisted by GC-olfactometry.

Optimization of the extraction conditions to investigate the volatile composition of papaya fruit involving headspace solid phase micro-extraction was carried out using multivariate strategies such as factorial design and response surface methodology. The performance of different combinations of time for reaching the equilibrium in the headspace and time for maximum extraction of volatiles was evaluated by GC-olfactometry of the extract (intensity of papaya characteristic aroma), number of peaks and total area in the chromatogram. Thirty-two compounds were identified by GC-MS under the optimized extraction conditions, the majority of which were aldehydes, both in number of compounds and area. Major compounds were δ-octalactone, ß-citral, benzaldehyde, heptanal, benzyl isothiocyanate, isoamyl acetate, γ-octalactone, (E)-linalool oxide and benzyl alcohol. Seven aldehydes and two other compounds are reported for the first time in papaya's volatile profile.

Yacon syrup: Food applications and impact on satiety in healthy volunteers.

Syrup obtained from yacon roots could be well positioned as a nutritional product due to its high fructooligosaccharides (FOS) content. Considering this, we examined the potential food applications of yacon syrup, using the focal group methodology, and its sensorial acceptability when incorporated in yogurt. The beneficial effects of the consumption of yacon syrup were studied over a 2-week period in a double-blind placebo-controlled experiment (namely Test A) and other consistent of only one day of yacon syrup consumption (namely Test B) were also evaluated. The doses of yacon syrup for both experiments were 8.74g of FOS/day. Energy intake, hunger, satiety, fullness and prospective food consumption were assessed with analogue scales at the end of each test. The results indicate that the yogurt was the food most suggested by the focus group, and the average of the scores given to the attributes when the yacon syrup was incorporated into a yogurt were: 7.78 for appearance; 7.72 for aroma; 7.02 for flavor and 6.96 for overall acceptability, corresponding to "like very much" and "like moderately". Furthermore, the results indicate that yacon syrup has a positive effect on appetite and its effect was dependent on gender and period of intervention, being statistically significant (P<0.05) in women, after 2-week period. These findings suggested that increasing FOS intake could help to increase satiety, and consequently, be helpful in the management of type 2-diabetes or control of the current high prevalence of overweight or obesity.

Influence of lactation stage and some flock management practices on sensory characteristics of goat milk from Brazilian Saanen breed.

This study evaluated the influence of lactation stage (early, middle, late) and management practices (milking hygiene and buck presence) on the sensory attributes of Saanen goat milk. Goats were randomly divided in four groups in respect of different milking sanitary procedures and the presence/absence of the buck in the barn. Milk samples were analyzed for sensory attributes including quantitative descriptive analysis (QDA) and acceptance. The milking hygiene practice caused no significant influence on microbiological parameters. Results of QDA revealed that the buck presence increased the characteristic odor of milk at the middle and late lactation stages. The off-odor and off-flavor descriptors showed a distinct response since a higher intensity of these sensory characteristics was noted in the samples obtained from goats maintained without the buck. Odor and flavor contributed most in characterizing the different samples regardless of the management practice and lactation stage. The acceptance of odor showed to be influenced only by the lactation stage, while the acceptance of flavor was only through the presence of the buck. Odor acceptance correlated negatively to off-odor and off-flavor, suggesting that these two sensory attributes impaired the preference for the aroma of the milk samples.