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Title: Effect of triacylglycerol composition on the properties of shortenings for puff pastry
Author: Macias, Paulina Garcia
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2012
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Abstract:
Twelve fat blends based on palm fractions, shea fractions and fully hardened soybean oil were combined with high oleic sunflower oil and studied for potential use as puff pastry shortenings. The fat blends had a lower saturated fatty acid content (28.3-32.0%) compared to a commercial puff pastry shortening (49.4%) and butter (65.9%). The saturated fat contained in the blends was formed by different triacylglycerol (TAG) structures containing mainly stearic acid, palmitic acid or a combination of both so that the fat blends contained different TAG composition and it was possible to assess the effect ofthe different TAG composition on their performance as puff pastry shortenings. The fat sources of the main TAGs were: Palm Stearin (POs), which contained tripalmitoyl glycerol (PPP) Palm Mid-fraction (PM F), which contained 1,3-dipalmitoyl-2-0Ieyl glycerol (POP) Interesterified Palm Mid-fraction (inPMF), which contained PPP, POP, 1,2-dipalmitoyl-3-0Ieyl glycerol (PPO) and 1-palmitoyl-2,3-dioleylglycerol (POO) Fully Hardened Soybean Oil (fhBO), which contained tristearoylglycerol (SSS) Shea Stearin (SHs), which contained 1,3-distearoyl-2-oelyl glycerol (SOS) Interesterified Shea Stearin (inSHs), which contained SSS, SOS and 1-stearoyl-2,3- dioleylglycerol (SOO) and 1,2-distearoyl-3-0Ieyl glycerol (SSO) High Oleic Sunflower Oil (HOSF), which contained trioleyl glycerol (000) The blends were formulated to systematically vary the ratio of trisatures (either PPP or SSS); 1,2- disaturates (either PPO or SSO) and 1,3-disaturates (either POP or SOS). The blends were processed on a pilot plant scale and their properties were studied The physical properties of the fat blends and their functionality as shortenings for puff pastry were assessed by their Solid Fat Content (SFC), polymorphism, melting and crystallisation profile, texture and production of a baked puff pastry product. The solid fat content showed that blends containing stearic acid had the highest SFC between 20 and 30°C (25.3-33.3% at 20°C and 19.8-24.2% at 30°C) compared to samples containing palmitic acid (18-23% at 20°C and 1.2-21.2% at 30°C). Above 30°C all samples commenced a decline in their SFC, the most affected being those containing disaturated TAGs and palmitic acid. The melting profile showed that higher melting TAGs were present in blends B1-B4 compared to blends containing mainly palmitic acid (A1-A4), where less energy was required for melting and crystallising the TAGs present. The main polymorph found was f3 in blends containing SOS, POP or a combination of both as their main TAG (blends A4, B4 and C4). Polymorph P' was also detected in the blends combined with B. Blends A3 and C3 which contained POO as their main TAGs crystallised mainly in the W polymorph. Puff pastry prepared with blend A1 (POs:HOSF 29:71), A4 (PMF:HOSF 41:59), B3 (inSHs:HOSF 38:62) and C3 (inPMF:inSHs:HOSF 19:20:61) was very hard. Blends A2 (POs:PMF:HOSF 13:19:68), B4 (SHs:HOSF 40:60), C2 (POs:PMF:fhBO:SHs: HOSF (9:12:4:12:63) and C4 (PMF:SHs:HOSF 20:21:59) were most similar to butter in the compressibility of the baked product and specific volume. It was found that puff pastry prepared from blends that contained SOS as the main saturates (blends B4, Cl, C2and C4) presented properties closer to butter than the other blends as they were similar to butter in compressibility of the baked product and had high specific volume. Blend C2 prepared with POs, PMF, fhBO, SHs and HOSF (9:12:4:12:63) produced a puff pastry product with better qualities than the rest of the fat blends and its textural properties such as specific volume (3.5 cm3/g), height (22.6 mm) and compression (138 g) were comparable to those obtained with butter. For this reason, it was selected to be optimised for use as a puff pastry shortening by increasing its saturated concentration from 33% to 34.6% and 37.6% and compared to a commercial puff pastry shortening with 49.4% total saturates. The main TAGs were PPP:SSS (2.5:1) and POP:SOS (1.1:1). Physical properties such as SFC, melting and crystallisation profile and yield stress were affected by the increasing levels in saturated fatty acid content. Microscopyand rheological analysis showed minor differences at the microstructural level and this was reflected in their performance in the puff pastry products. The blends compared well with commercial puff pastry and butter. It was concluded that a high SFC and melting point, indicative of good plasticity, are required in the making of puff pastry products and that the level of microstructure provided by disaturated TAGs with the configuration saturated-unsaturated-saturated is desirable as they promote crystallisation in the ~ polymorph, a good lift and specific volume, favouring the production of puff pastry products with comparable characteristics to those obtained with butter and the commercial puff pastry shortening.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.578080  DOI: Not available
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