Quantitative Determination of Phenolic Acids and Flavonoids in Fresh Whole Crop Rice, Silage, and Hay at Different Harvest Periods

Whole crop rice (WCR) is used as an important feed for livestock ruminants. In this study, “Yeongwoo” variety WCR (cultivated on the Korean peninsula) was harvested at three different maturity stages (booting, heading, and milk) and their phenolic acid and flavonoid profiles in the lactic acid bacteria (LAB)-inoculated and noninoculated silage, hay, and fresh freeze-dried WCR extract were quantified. The alterations in the phenolic and flavonoid contents of the selected WCR during maturation in different samples were analyzed by the High-Performance Liquid Chromatography- Diode Array Detector (HPLC–DAD) technique. The six phenolics (caffeic acid, ferulic acid, p-coumaric acid, chlorogenic acid, dihydroxy benzoic acid, and prophyl gallate) and six flavonoids (rutin hydroxide, luteolin, kaempferol, vitexin, myricetin, and quercetin) were noted to have slight differences between the LAB-inoculated and noninoculated silage samples; however, the phenolics and flavonoids were higher in hay WCR at the milk stage compared to the silage and fresh freeze-dried samples. The results indicate that WCR harvest times have different phenolic compounds in the WCR silage, hay, and fresh samples. The phenolic and flavonoid compounds were higher (p < 0.05) with the increase in maturity (Stage 1–3). The stage of WCR maturity was positively related (p < 0.05) to the amount of phenolic acid and flavonoid contents (µg/g) in hay, silage, and fresh freeze-dried extract. We observed the WCR had high amounts of phenolic acid and flavonoid concentrations at milk stage (Stage 3) hay (quercetin, kaemferol, luteolin, ferulic acid, caffeic acid, and coumaric acid were 1.28, 1.29, 0.54, 1.54, 1.92, and 1.81 µg/g, respectively) compared with the booting and heading stages (Stages 1 and 2), with acceptable accuracy on a pilot scale. Based on these results, it could be concluded that LAB (Lactobacillus plantarum)-inoculated whole crop rice silage (WCRS) did not affect the phenolics and flavonoids of secondary plant metabolites in fermented silage. However, phenolics and flavonoids were of higher rations in WCR at the milk stage. Furthermore, this phenolic acid and flavonoid effect needs to be confirmed using large-scale in vivo analysis.

The Quality of Freeze-Dried and Rehydrated Blueberries Depending on their Size and Preparation for Freeze-Drying

A significant increase in highbush blueberry plantings has been observed annually. However, there is a problem with the handling of fruit that does not meet the requirements for dessert berries. One of the methods to use the fruit is drying. The research was conducted in the Department of Horticulture at the West Pomeranian University of Technology in Szczecin. The fruit was harvested at a plantation specialising in the production of highbush blueberry from irrigated and non-irrigated plots. This study aimed to assess how cutting or pricking highbush blueberry fruit affects the duration of the sublimation drying process – freeze-drying. The biological value of fresh, freeze-dried, and rehydrated fruit was assessed. The amount of fruit left on bushes depended on the weather prevailing in the growing season, especially during the harvest period. The mass of fruit left on the bushes was approx. 1 to 2 t/ha. Although these fruits were small, they had a very high biological value. After freeze-drying and rehydration, the blueberry fruit retained their colour, high content of polyphenols and showed high antidiabetic activity and antioxidant capacity. The large fruit reached the moisture content of approx. 12%, which ensures safe storage and the appropriate texture, after 46 hours of drying, and the smaller fruit - after 32 hours. Fruit cutting or pricking reduced the drying time by half. Reducing this time decreased drying costs and increased biological value.

Evaluation of Pediococcus pentosaceus SP2 as Starter Culture on Sourdough Bread Making

In the present study, a novel Pediococcus pentosaceus SP2 strain, recently isolated from kefir grains, was evaluated as a starter culture in sourdough bread making. The novel starter was applied in fresh, freeze-dried, and freeze-dried immobilized (on wheat bran) form. The type of culture (fresh, freeze-dried, immobilized cells) influenced the bread characteristics. Specifically, the application of freeze-dried immobilized cells led to higher total titratable acidity (TTA) values (9.81 mL NaOH N/10), and the produced bread presented higher resistance to mold and rope spoilage. Moreover, the produced sourdough breads were significantly better in terms of pH, TTA, organic acids content, and resistance to mold and rope spoilage, compared to breads made with a commercial, wild microbiota, sourdough. The organic acids content was also significantly higher than the commercial sourdough sample (2.93 g/kg lactic acid; 1.01 g/kg acetic acid). Determination of volatile compounds through solid-phase microextraction (SPME) gas chromatography/mass spectrometry (GC/MS) analysis and sensorial assessments indicated no significant differences between the tested sourdough breads.