Pennsylvania Folklife Vol. 14, No. 1

• The Oley Valley Basketmaker • The Sheen of Copper • Pennsylvania Corncribs • Land-Clearing in Lycoming County, Pennsylvania • Funerals in My Childhood Days • Folk Medicine from Western Pennsylvania • Peddlers I Rememberhttps://digitalcommons.ursinus.edu/pafolklifemag/1017/thumbnail.jp

Identification of emulsifier potato peptides by bioinformatics: application to omega-3 delivery emulsions and release from potato industry side streams

We are grateful for the financial support from Innovation Fund Denmark (Grant nr: 7045-00021B, PROVIDE project). We also acknowledge K.M.C. amba (Brande, Denmark) and A.K.V. amba (Langholt, Denmark) for providing the potato samples used in this study.In this work, we developed a novel approach combining bioinformatics, testing of functionality and bottom-up proteomics to obtain peptide emulsifiers from potato side-streams. This is a significant advancement in the process to obtain emulsifier peptides and it is applicable to any type of protein. Our results indicated that structure at the interface is the major determining factor of the emulsifying activity of peptide emulsifiers. Fish oil-in-water emulsions with high physical stability were stabilized with peptides to be predicted to have facial amphiphilicity: (i) peptides with predominantly α-helix conformation at the interface and having 18–29 amino acids, and (ii) peptides with predominantly β-strand conformation at the interface and having 13–15 amino acids. In addition, high physically stable emulsions were obtained with peptides that were predicted to have axial hydrophobic/hydrophilic regions. Peptides containing the sequence FCLKVGV showed high in vitro antioxidant activity and led to emulsions with high oxidative stability. Peptide-level proteomics data and sequence analysis revealed the feasibility to obtain the potent emulsifier peptides found in this study (e.g. γ-1) by trypsin-based hydrolysis of different side streams in the potato industry.Innovation Fund Denmark 7045-00021

Anastrozole versus tamoxifen for the prevention of locoregional and contralateral breast cancer in postmenopausal women with locally excised ductal carcinoma in situ (IBIS-II DCIS): a double-blind, randomised controlled trial

Background Third-generation aromatase inhibitors are more effective than tamoxifen for preventing recurrence in postmenopausal women with hormone-receptor-positive invasive breast cancer. However, it is not known whether anastrozole is more effective than tamoxifen for women with hormone-receptor-positive ductal carcinoma in situ (DCIS). Here, we compare the efficacy of anastrozole with that of tamoxifen in postmenopausal women with hormone-receptor-positive DCIS. Methods In a double-blind, multicentre, randomised placebo-controlled trial, we recruited women who had been diagnosed with locally excised, hormone-receptor-positive DCIS. Eligible women were randomly assigned in a 1:1 ratio by central computer allocation to receive 1 mg oral anastrozole or 20 mg oral tamoxifen every day for 5 years. Randomisation was stratified by major centre or hub and was done in blocks (six, eight, or ten). All trial personnel, participants, and clinicians were masked to treatment allocation and only the trial statistician had access to treatment allocation. The primary endpoint was all recurrence, including recurrent DCIS and new contralateral tumours. All analyses were done on a modified intention-to-treat basis (in all women who were randomised and did not revoke consent for their data to be included) and proportional hazard models were used to compute hazard ratios and corresponding confidence intervals. This trial is registered at the ISRCTN registry, number ISRCTN37546358. Results Between March 3, 2003, and Feb 8, 2012, we enrolled 2980 postmenopausal women from 236 centres in 14 countries and randomly assigned them to receive anastrozole (1449 analysed) or tamoxifen (1489 analysed). Median follow-up was 7·2 years (IQR 5·6–8·9), and 144 breast cancer recurrences were recorded. We noted no statistically significant difference in overall recurrence (67 recurrences for anastrozole vs 77 for tamoxifen; HR 0·89 [95% CI 0·64–1·23]). The non-inferiority of anastrozole was established (upper 95% CI <1·25), but its superiority to tamoxifen was not (p=0·49). A total of 69 deaths were recorded (33 for anastrozole vs 36 for tamoxifen; HR 0·93 [95% CI 0·58–1·50], p=0·78), and no specific cause was more common in one group than the other. The number of women reporting any adverse event was similar between anastrozole (1323 women, 91%) and tamoxifen (1379 women, 93%); the side-effect profiles of the two drugs differed, with more fractures, musculoskeletal events, hypercholesterolaemia, and strokes with anastrozole and more muscle spasm, gynaecological cancers and symptoms, vasomotor symptoms, and deep vein thromboses with tamoxifen. Conclusions No clear efficacy differences were seen between the two treatments. Anastrozole offers another treatment option for postmenopausal women with hormone-receptor-positive DCIS, which may be be more appropriate for some women with contraindications for tamoxifen. Longer follow-up will be necessary to fully evaluate treatment differences

Nonlinear interfacial rheology and atomic force microscopy of air-water interfaces stabilized by whey protein beads and their constituents

In recent years, food-grade Pickering particles have gained considerable interest, because of their ability to form stable emulsions and foams. Such Pickering stabilizers are often produced by aggregation of proteins, which typically results in a mixture of cross-linked particles and unbound proteins (smaller constituents). This study focuses on the possible contribution to the interfacial behaviour of these smaller constituents in whey protein isolate (WPI) bead suspensions, which are produced by cold-gelation of WPI aggregates. To understand the interfacial properties of the total mixture, we have studied the involved structures and interactions hierarchically, from native WPI, to aggregates, and finally gel beads. Air-water interfaces were subjected to large amplitude oscillatory dilatation (LAOD) and shear (LAOS) using a drop tensiometer and a double wall ring geometry. The non-linear responses were analysed using Lissajous plots. The plots of native WPI- and aggregates-stabilized interfaces showed a rheological behaviour of a viscoelastic solid, while bead-stabilized interfaces tended to have a weaker and more fluid-like behaviour. The interfacial microstructure was analysed by imaging Langmuir-Blodgett films of the protein systems using atomic force microscopy (AFM). The native WPI and aggregate films had a highly heterogeneous structure in which the proteins form a dense clustered network. The beads are randomly distributed throughout the film, separated by large areas, where smaller proteinaceous material is present. This smaller and surface-active material present in the bead suspensions plays an important role in interface stabilization, and could also largely influence the macroscopic properties of interface-dominated systems.</p

Competition of rapeseed proteins and oleosomes for the air-water interface and its effect on the foaming properties of protein-oleosome mixtures

There is an increasing interest to apply oleosomes (plant oil storage organelles) as natural oil droplets in food systems. Lipids are usually known to be detrimental for protein-stabilised foams due to the weakening of interactions between adsorbed proteins, or by forming oil bridges between two protein surfaces. Both mechanisms can lead to film rupture, and thereby destabilise protein-stabilised foams. Little is known about the influence of oleosomes on protein-stabilised interfaces and foams. Therefore, these properties were studied for rapeseed protein–oleosome mixtures at various protein concentrations and ratios. At 0.1 and 0.2% (w/w) protein content, oleosomes were found to co-adsorb with proteins at the interface, followed by rupture of oleosomes and release of triacylglycerols and phospholipids. This led to weaker in-plane interactions between adsorbed proteins. As a result, the foamability and foam stability of protein-oleosome systems were substantially lower compared to systems made with pure proteins. At 0.5 and 1.0% (w/w) protein content, the rapeseed proteins were found to dominate the interfacial properties. The proteins formed a dense solid-like layer at such high concentrations, which prevented the oleosomes from co-adsorbing at the interface. Also, in foam systems at high protein concentrations, the proteins seemed to outcompete the oleosomes for the interface, leading to higher foam stability. Here, we have demonstrated that the detrimental influence of oleosomes on protein-stabilised interfaces and foams can be controlled by varying the amount of oleosomes and rapeseed proteins in the mixture, which is a promising outcome to further utilise oleosomes in aerated food systems.</p

Nonlinear interfacial rheology and atomic force microscopy of air-water interfaces stabilized by whey protein beads and their constituents

In recent years, food-grade Pickering particles have gained considerable interest, because of their ability to form stable emulsions and foams. Such Pickering stabilizers are often produced by aggregation of proteins, which typically results in a mixture of cross-linked particles and unbound proteins (smaller constituents). This study focuses on the possible contribution to the interfacial behaviour of these smaller constituents in whey protein isolate (WPI) bead suspensions, which are produced by cold-gelation of WPI aggregates. To understand the interfacial properties of the total mixture, we have studied the involved structures and interactions hierarchically, from native WPI, to aggregates, and finally gel beads. Air-water interfaces were subjected to large amplitude oscillatory dilatation (LAOD) and shear (LAOS) using a drop tensiometer and a double wall ring geometry. The non-linear responses were analysed using Lissajous plots. The plots of native WPI- and aggregates-stabilized interfaces showed a rheological behaviour of a viscoelastic solid, while bead-stabilized interfaces tended to have a weaker and more fluid-like behaviour. The interfacial microstructure was analysed by imaging Langmuir-Blodgett films of the protein systems using atomic force microscopy (AFM). The native WPI and aggregate films had a highly heterogeneous structure in which the proteins form a dense clustered network. The beads are randomly distributed throughout the film, separated by large areas, where smaller proteinaceous material is present. This smaller and surface-active material present in the bead suspensions plays an important role in interface stabilization, and could also largely influence the macroscopic properties of interface-dominated systems.</p

Foams and air-water interfaces stabilised by mildly purified rapeseed proteins after defatting

Rapeseed protein isolate has promising functional properties (e.g. emulsifying and foaming), but is often extracted with intensive purification steps. This requires a considerable use of resources and damages protein functionality regarding, for instance, foam stabilization. We studied the interfacial and foaming properties of a mildly obtained rapeseed protein concentrate that contained oleosomes, and of its derived defatted rapeseed protein concentrate after solvent-based defatting. The air-water interfaces were deformed with large amplitude dilatational and shear deformations, which were analysed with Lissajous plots. At low bulk concentrations (0.01% w/w), the rapeseed protein-stabilised interfaces behaved as viscoelastic solids. The interfacial films became weaker and more stretchable at higher concentrations, suggesting that more non-protein components interfere with the intermolecular interactions between the adsorbed proteins at higher bulk concentrations. We confirmed the presence of such non-protein components at the interface by analysing Langmuir-Blodgett films with atomic force microscopy. The stability and air bubble size of foams prepared with either rapeseed protein concentrate or defatted rapeseed protein concentrate were similar. Mild purification of rapeseed resulted in a protein concentrate containing lipids in their native oleosome form, which have a minor destabilizing effect on foams. We conclude that mild purification is a suitable method to obtain sustainably produced protein concentrates with promising foaming properties.</p

Air-water interfacial and foaming properties of whey protein - sinapic acid mixtures

Phenols are widely present in plants and often are co-extracted in plant protein extracts, while such components could influence the protein's interface and foam stabilising properties. In this study, the influence of rapeseed phenol sinapic acid (SA) on the interfacial and foaming properties of a well characterised model protein, whey protein isolate (WPI), was investigated. WPI formed strong viscoelastic interfacial layers, and addition of SA reduced the surface dilatational modulus by 25%. Turning SA into its active oxidised form in the WPI-SA mixtures led to protein aggregation, resulting in a further decrease of the modulus by 40%. Removal of unbound phenols induced a slight increase of the dilatational modulus, but the interfacial layer strength did not fully recover to that made with pure WPI, suggesting binding of phenols to proteins, and thus influencing the protein interface stabilising properties. Foams stabilised by WPI-SA mixtures had a shorter foam half-life time (130–180 min) than foams stabilised by pure WPI (260 min). Our data are thus in line with the observation that a lower surface dilatational modulus leads to a lower foam stability. Yet, the foam stability did not recover to the original values of pure WPI-stabilised foams after removal of unbound phenols. In conclusion, the presence of SA resulted in a decrease in interfacial layer strength and foam stability. We conclude that in producing protein extracts from rapeseed or other phenol-rich plant sources, the presence and oxidation of phenols should thus be considered.</p