Synergistic mechanism of steam blanching and freezing conditions on the texture of frozen yellow peaches based on macroscopic and microscopic properties

Freezing and blanching are essential processing steps in the production of frozen yellow peaches, inevitably leading to texture softening of the fruit. In this study, the synergistic mechanism of stem blanching, freezing conditions (-20°C, -40°C, -80°C, and liquid nitrogen [-173°C]), and sample sizes (cubes, slices, and half peaches) on macroscopic properties of texture, cellular structure, and ice crystal size distribution of frozen yellow peaches were measured. Blanching enhanced the heat and mass transfer rates in the subsequent freezing process. For nonblanched samples, cell membrane integrity was lost at any freezing rate, causing a significant reduction in textural quality. Slow freezing further exacerbated the texture softening, while the ultra-rapid freezing caused structural rupture. For blanched samples, the half peaches softened the most. The water holding capacity and fracture stress were not significantly affected by changes in freezing rate, although the ice crystal size distribution was more susceptible to the freezing rate. Peach cubes that had undergone blanching and rapid freezing (-80°C) experienced 4% less drip loss than nonblanched samples. However, blanching softened yellow peaches more than any freezing conditions. The implementation of uniform and shorter duration blanching, along with rapid freezing, has been proven to be more effective in preserving the texture of frozen yellow peaches. Optimization of the blanching process may be more important than increasing the freezing rate to improve the textural quality of frozen yellow peaches.

Comparative study on nutritional and technological properties of two varieties of black wheat flour and their noodle-making potential

Comparative studies were conducted on physicochemical and technological properties of two black wheat (BW) varieties (cultivated in Shanxi Agricultural University) and their noodle-making potential. Whole-grain BW noodles showed acceptable cooking loss (≤10%) and strong antioxidant capacity. However, their textural quality remains to be enhanced. Regarding refined flour (RF) of the two BW varieties, Yunhei 14207 showed more anthocyanins, brighter color, and greater thermal stability (as reflected by the higher pasting temperature). 16W16 resulted in greater gluten content and better gluten quality of flour and higher dough stability, which contributed to the lower cooking loss and stronger tensile property of noodles. RF noodles of Yunhei 14207 displayed brighter appearance, although they had weaker tensile property. The stronger gluten network in noodles of 16W16 protected phenolics from release and degradation during drying, cooking, and steaming. Despite phenolics loss, RF noodles of Yunhei 14207 showed antioxidant capacity up to 14.97 mg TE/100 g. This research would promote understanding of characteristics of BW varieties. Considering the stronger gluten network of 16W16, its fortification in common wheat noodles at high proportion (>50%) may be promising to develop antioxidant noodles with further improved sensory quality.

Food Quality Profile of Pounded Yam and Implications For Yam Breeding

BACKGROUND

Assessment of key preferred quality traits in pounded yam, a popularly consumed yam food product in West Africa, is often done through sensory evaluation. Such assessment is time-consuming and results may be biased. Therefore, there is a need to develop objective, high-throughput methods to predict the quality of consumer-preferred traits in pounded yam. This study focused on how key quality traits in pounded yam proposed to yam breeders were determined, measured by biophysical and biochemical methods, in order to shorten the breeding selection cycle through adoption of these methods by breeders.

RESULTS

Consumer tests and sensory quality descriptive analysis (QDA) validated that preferred priority quality traits in pounded yam were related to textural quality: smooth, stretchable, moldable, slightly sticky and moderately hard) and color (white, cream or light yellow). There were significant correlations between sensory textural quality attributes cohesiveness/moldability, hardness, and adhesiveness/stickiness, with textural quality measurements from instrumental texture profile analysis (TPA). Color measurement with chromameter (L*, a*, and b*) parameters agreed with that of sensory evaluation and can replace the sensory panel approach. The smoothness (R² =1.00), stickiness (R² =1.00), stretchability (R² =1.00), hardness (R² =0.99), and moldability (R² = 0.53) of pounded yam samples can be predicted by the starch, amylose, and protein contents of yam tubers estimated by near-infrared spectroscopy.

CONCLUSION

TPA and Hunter colorimeter can be used as medium-high throughput methods to evaluate the textural quality and color of pounded yam in place of the sensory panelists. This article is protected by copyright. All rights reserved.

The Impacts of Different Pea Protein Isolate Levels on Functional, Instrumental and Textural Quality Parameters of Duck Meat Batters

This study aimed to investigate the effect of pea protein isolate (PPI) on the functional, instrumental and textural quality parameters of duck meat batters (DMB). Ground duck breast meat was mixed with different concentrations of PPI (0%, 3%, 6% or 9%, w/w) to prepare DMB. The color, cooking yield, water-holding capacity, water distribution and migration, rheological properties and texture profile of the DMB were evaluated. The results showed that the L* value of the gel decreased and the b* value increased with the increasing pea protein addition. The cooking yield and water-holding capacity showed a gradual increase, but the difference was not significant (p > 0.05). Compared with the control, the storage modulus (G′) and loss modulus (G″) were higher at the beginning and at the end and increased with the addition of pea protein, which was in accordance with the Fourier series relationship. The hardness, chewiness and gumminess of the gels gradually increased; on the contrary, the springiness and cohesiveness first increased and then decreased, respectively, reaching a maximum value of 0.96 and 0.81 when the addition amount reached 6%. Adding pea protein to the gels not only increased the area of immobilized water but also decreased the area of free water, thus improving the water-holding capacity of the batters. Therefore, pea protein can promote the formation of a stable and elastic network structure of duck meat batters.

Effects of Pangasius (Pangasius hypophthalmus) and Skipjack Tuna (Sarda orientalis) mince blend on the quality of fish products: Ways to utilize resources and nutrition in Bangladesh

This study was conducted with the aims of utilizing the resources and analyzing the quality of value-added fish products, fish ball made from a fish mince blend of pangasius (Pangasius hypophthalmus) and skipjack tuna (Sarda orientalis) (ratios P100:T0, P75:T25, P50:T50, P25:T75, P0:T100), under two cooking processes (two-step heating and autoclaving). The textural quality (softness/firmness [S/F]; chewiness/rubberiness [C/R]; and folding test [FT]) and the nutritional quality of the fish products were determined by the sensory method and AOAC method, respectively. The results showed that tuna had higher utilization than pangasius. The products from the washed fish mince blend showed better textural properties with two-step heating (50℃ for 60 min and 100℃ for 30 min) than with autoclaving (120℃, 15Ib/Inc2 for 15 min) and unwashed process. Of the five fish mince blend ratios, P50:T50 showed significant higher textural properties (FT, S/F, and C/R values) than the other ratios (p < .05). Further improvements in textural qualities were observed when the mince blend was washed with different salt solutions (0.1% NaCl, KCl, CaCl2, and MgCl2). Whitish or bright color attributes were obtained from pangasius mince, which became darker proportionately with increasing proportions of tuna mince (p < .05). The texture, color, and nutritional quality of the fish products were affected by washing, heating, and the compositional differences in the fish species. Thus, value-added fish products based on a fish mince blend could contribute to an increase in total resource utilization and nutritional security in Bangladesh.