Food and Nutritional Sciences

Statistical approaches to access the effect of Lactobacillus sakei culture and ultrasound frequency on fatty acid profile of beef jerky

Tue, 12 Dec 2017 00:00:00 GMT

Statistical approaches to access the effect of Lactobacillus sakei culture and ultrasound frequency on fatty acid profile of beef jerky Ojha, K. Shikha; Harrison, Sabine M.; Brunton, Nigel P.; Kerry, Joseph P.; Tiwari, Brijesh K. The objective of this study was to investigate the effect of ultrasonic frequencies and drying time on fatty acid profiles of beef jerky samples possessing different microbial compositions. Beef slices were cured using curing solutions formulated both with and without Lactobacillus sakei. Curing was carried out for 18 h at 4 °C prior to hot air drying at 60 °C for 4 h. Jerky samples from both treatment groups were then subjected to ultrasonic frequencies of 25 kHz, 33 kHz and 45 kHz for 30 min. Beef jerky samples were subsequently analysed for fatty acid profile using Gas Chromatography. In the present study, beef slices showed a high level of MUFAs, which accounted for 45.6–53.8%, followed by the SFAs (36.3–47.8%) and PUFAs (4.8–13.7%), respectively. Results demonstrated a significant effect of beef jerky processing on fatty acid profile. Various correlation analyses showed that changes in fatty acid profiles were significantly affected by individual and/or interactive effects of L. sakei, drying time and ultrasonic frequency.

Plasmin activity in Manchega ewe milk: The effect of lactation, parity and health of the udder, and its influence on milk composition and rennet coagulation

Tue, 17 Oct 2017 00:00:00 GMT

Plasmin activity in Manchega ewe milk: The effect of lactation, parity and health of the udder, and its influence on milk composition and rennet coagulation Caballero-Villalobos, J.; Garzón, A. I.; Martínez Marín, A. L.; Arias, R.; Ciocia, Felicia; McSweeney, Paul L. H. Milk from 40 Manchega ewes was collected monthly and analysed during a complete lactation (5 months). Milk samples were classified by their origin in 3 categories, termed PR (primiparous ewes), M1 (multiparous ewes with no damage of the udder in the previous lactation) and M2 (multiparous ewes with udder damage in the previous lactation). The influence on plasmin of several factors as stage of lactation, parity, somatic cell count and udder health status was studied, as well as the effect of plasmin activity on milk composition and rennet coagulation. Plasmin activity decreased throughout lactation but was not affected by parity or somatic cell count (P > 0.05). A strong negative correlation was found between plasmin activity and protein (especially casein), presumably due to the proteolysis of ß-casein. Plasmin also worsened rennet coagulation, increasing rennet clotting time (RCT) and negatively affecting curd firmness (A60), especially in multiparous ewes. However, the good health condition in the herd may have camouflaged some effects of plasmin over renneting.

Processed red meat contribution to dietary patterns and the associated cardio-metabolic outcomes

Wed, 23 Aug 2017 00:00:00 GMT

Processed red meat contribution to dietary patterns and the associated cardio-metabolic outcomes Lenighan, Yvonne M.; Nugent, Anne P.; Li, Kaifeng F.; Brennan, Lorraine; Walton, Janette; Flynn, Albert; Roche, Helen M.; McNulty, Breige A. Evidence suggests that processed red meat consumption is a risk factor for CVD and type 2 diabetes (T2D). This analysis investigates the association between dietary patterns, their processed red meat contributions, and association with blood biomarkers of CVD and T2D, in 786 Irish adults (18–90 years) using cross-sectional data from a 2011 national food consumption survey. All meat-containing foods consumed were assigned to four food groups (n 502) on the basis of whether they contained red or white meat and whether they were processed or unprocessed. The remaining foods (n 2050) were assigned to twenty-nine food groups. Two-step and k-means cluster analyses were applied to derive dietary patterns. Nutrient intakes, plasma fatty acids and biomarkers of CVD and T2D were assessed. A total of four dietary patterns were derived. In comparison with the pattern with lower contributions from processed red meat, the dietary pattern with greater processed red meat intakes presented a poorer Alternate Healthy Eating Index (21·2 (sd 7·7)), a greater proportion of smokers (29 %) and lower plasma EPA (1·34 (sd 0·72) %) and DHA (2·21 (sd 0·84) %) levels (P<0·001). There were no differences in classical biomarkers of CVD and T2D, including serum cholesterol and insulin, across dietary patterns. This suggests that the consideration of processed red meat consumption as a risk factor for CVD and T2D may need to be re-assessed.

The eating quality of beef from young dairy bulls derived from two breed types at three ages from two different production systems

Sat, 08 Jul 2017 00:00:00 GMT

The eating quality of beef from young dairy bulls derived from two breed types at three ages from two different production systems Nian, Yingqun; Kerry, Joseph P.; Prendiville, P.; Allen, P. Expansion of the Irish dairy herd has led to more dairy breed male calves being available for beef production. This study investigated the physico-chemical and sensory characteristics of beef from Holstein–Friesian (HF) and Jersey × HF (JEX) young bulls fed pasture grass only or pasture grass plus 2 kg concentrate during their first grazing season and slaughtered at 15, 19 or 22 mo of age. Longissimus thoracis (LT) muscles were collected from 67 carcasses. Postmortem pH, ultimate pH (pHu), meat colour, chemical composition, collagen content and solubility were evaluated. After ageing for 21 d, Warner-Bratzler shear force and cooking loss were determined, and assessments by a trained sensory panel were conducted. Meat from older animals was darker. The pHu, moisture and ash contents decreased, while residual roast beef flavour length increased with age. However, increasing age to slaughter did not negatively influence tenderness. JEX beef had lower cooking loss, was darker and redder, in addition to having higher sensory scores for initial tenderness and fattiness than HF beef. Warner-Bratzler variables were positively correlated with cooking loss and chewiness and were negatively correlated with intramuscular fat (IMF) content, soluble collagen and initial tenderness. In summary, most young dairy bull beef samples were acceptably tender after 21 d of ageing and half of them had acceptable IMF content. Slaughter age affected beef colour, pHu, chemical composition and flavour length. The eating quality of meat from the JEX breed type was considered to be superior to that of the HF breed type. Diet during the first season had no effect on meat quality traits.